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  • 1
    Electronic Resource
    Electronic Resource
    Polyamines in Helianthus annuus L. during Germination under Salt Stress (1997)
    Springer
    Journal of plant growth regulation 16 (1997), S. 205-211 
    Details
    ISSN: 1435-8107
    Keywords: Key Words. Polyamines—Salt stress—ADC—ODC—Polyamine biosynthesis inhibitors—Helianthus annuus L.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. The level of the three main polyamines putrescine, spermidine, and spermine and the biosynthetic enzyme arginine decarboxylase (ADC) decreased in Helianthus annuus L. seedlings subjected to increasing (50, 100, and 150 mm) NaCl concentrations. The pattern of polyamines in control plants increased during the initial 72 h and then reached a plateau. The putrescine level showed an increase of 370% after 72 h of development. The lower salt treatment slightly diminished the overall polyamine content. The highest NaCl concentration (150 mm) induced a strong putrescine diminution (from 381 to 78.9 nmol g−1 FW) at 72 h whereas a small decrease in ADC activity was detected. ODC was detected in neither control nor treated plantlets during the experimental period. The level of spermidine also decreased, but the magnitude of the decay was less pronounced than putrescine. The fact that ODC was not detected and ADC activity followed a pattern similar to that of putrescine led us to suppose that the variation in putrescine content could be attributed entirely to the decrease in ADC activity. α-Difluoromethylarginine and α-difluoromethylornithine (ADC and ODC inhibitor, respectively) did not inhibit but delayed the onset of germination of sunflower seeds, and α-difluoromethylornithine increased the content of spermidine and spermine. The present data suggest that polyamines could be involved in the germination process of H. annuus seeds and in response to salt stress.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00006997
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    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Oxaliplatin as single agent in previously untreated colorectal carcinoma patients: A phase II multicentric study (1998)
    Springer
    Annals of oncology 9 (1998), S. 105-108 
    Details
    ISSN: 1569-8041
    Keywords: advanced colorectal carcinoma ; oxaliplatin ; phase II study
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Background: Oxaliplatin is a new cytotoxic agent from the diaminocyclohexane family with proven antitumor activity against colon cancer cell lines. Activity in patients with colorectal carcinoma previously treated with 5-fluorouracil has been studied in three single-agent phase II trials, showing a reproducible response rate of 10%. Here we report a phase II trial with oxaliplatin as a first-line chemotherapy for metastatic colorectal cancer. Patients and methods: Twenty-five patients were entered in the study. All of them had metastatic disease without previous chemotherapy, and at least one lesion had to be measurable by computed tomography (CT). Therapy consisted of a two-hour infusion of oxaliplatin at a dose of 130 mg/m2 every 21 days. Results: The overall response rate determined by investigators was 20% (95% CI, 6.8%–40.7%). Eight patients (32%) had stable disease. The median time to disease progression in responders was six months (range four to nine). The median progression-free survival was four months and median overall survival 14.5 months (95% CI, 10–20 months). The main toxic effects were peripheral neuropathy (92%) and laryngopharyngeal dysesthesia (75%). No severe grade 3–4 neurotoxicities (NCI-CTC) were found. Gastrointestinal and hematological toxicities were mild. Conclusions: Oxaliplatin is an active agent in first-line chemotherapy for advanced colorectal cancer. It was well tolerated, caused no toxic deaths, had low hematotoxicity, well controlled gastrointestinal toxicity, and frequent but mild peripheral neurological symptoms. Therefore, it is of interest to associate oxaliplatin with other active compounds.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008200825886
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Plant regeneration and thiophene formation in tissue cultures of Tagetes mendocina (1993)
    Springer
    Plant cell, tissue and organ culture 35 (1993), S. 211-215 
    Details
    ISSN: 1573-5044
    Keywords: Compositae ; biocides ; organogenesis ; secondary metabolites
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Plants of the wild species Tagetes mendocina were regenerated, via organogenesis, from explants and callus cultures, and the occurrence of biocidal metabolites, thiophenes, by such undifferentiated tissues and regenerated plants was investigated. Differences between explant sources were apparent in terms of their competence for dedifferentiation and subsequent organogenesis. Leaf-derived cultures were more responsive than the root-derived ones. Biochemical studies revealed that the plants produced were capable of synthezising thiophene like-compounds following in vitro regeneration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00037272
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  • 4
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    Database of diazotrophs in global ocean: abundance, biomass and nitrogen fixation rates (2012)
    Copernicus Publications (EGU)
    In:  Earth System Science Data, 4 (1). pp. 47-73.
    Details
    Publication Date: 2020-05-13
    Description: Marine N2 fixing microorganisms, termed diazotrophs, are a key functional group in marine pelagic ecosystems. The biological fixation of dinitrogen (N2) to bioavailable nitrogen provides an important new source of nitrogen for pelagic marine ecosystems and influences primary productivity and organic matter export to the deep ocean. As one of a series of efforts to collect biomass and rates specific to different phytoplankton functional groups, we have constructed a database on diazotrophic organisms in the global pelagic upper ocean by compiling about 12 000 direct field measurements of cyanobacterial diazotroph abundances (based on microscopic cell counts or qPCR assays targeting the nifH genes) and N2 fixation rates. Biomass conversion factors are estimated based on cell sizes to convert abundance data to diazotrophic biomass. The database is limited spatially, lacking large regions of the ocean especially in the Indian Ocean. The data are approximately log-normal distributed, and large variances exist in most sub-databases with non-zero values differing 5 to 8 orders of magnitude. Reporting the geometric mean and the range of one geometric standard error below and above the geometric mean, the pelagic N2 fixation rate in the global ocean is estimated to be 62 (52–73) Tg N yr−1 and the pelagic diazotrophic biomass in the global ocean is estimated to be 2.1 (1.4–3.1) Tg C from cell counts and to 89 (43–150) Tg C from nifH-based abundances. Reporting the arithmetic mean and one standard error instead, these three global estimates are 140 ± 9.2 Tg N yr−1, 18 ± 1.8 Tg C and 590 ± 70 Tg C, respectively. Uncertainties related to biomass conversion factors can change the estimate of geometric mean pelagic diazotrophic biomass in the global ocean by about ±70%. It was recently established that the most commonly applied method used to measure N2 fixation has underestimated the true rates. As a result, one can expect that future rate measurements will shift the mean N2 fixation rate upward and may result in significantly higher estimates for the global N2 fixation. The evolving database can nevertheless be used to study spatial and temporal distributions and variations of marine N2 fixation, to validate geochemical estimates and to parameterize and validate biogeochemical models, keeping in mind that future rate measurements may rise in the future. The database is stored in PANGAEA (doi:10.1594/PANGAEA.774851).
    Type: Article , PeerReviewed
    Format: text
    Format: text
    DOI: 10.5194/essd-4-47-2012
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 5
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    Extracting Data from Disparate Sources for Agent-Based Disease Spread Models (2013)
    Hindawi
    Details
    Publication Date: 2013-03-07
    Description: This paper presents a review and evaluation of real data sources relative to their role and applicability in an agent-based model (ABM) simulating respiratory infection spread a large geographic area. The ABM is a spatial-temporal model inclusive of behavior and interaction patterns between individual agents. The agent behaviours in the model (movements and interactions) are fed by census/demographic data, integrated with real data from a telecommunication service provider (cellular records), traffic survey data, as well as person-person contact data obtained via a custom 3G smartphone application that logs Bluetooth connectivity between devices. Each source provides data of varying type and granularity, thereby enhancing the robustness of the model. The work demonstrates opportunities in data mining and fusion and the role of data in calibrating and validating ABMs. The data become real-world inputs into susceptible-exposed-infected-recovered (SEIR) disease spread models and their variants, thereby building credible and nonintrusive models to qualitatively model public health interventions at the population level.
    Print ISSN: 2090-2972
    Electronic ISSN: 2090-2980
    Topics: Medicine
    Published by Hindawi
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  • 6
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    Longitudinal variability of diazotroph abundances in the subtropical North Atlantic Ocean (2016)
    Oxford University Press
    Details
    Publication Date: 2016-06-04
    Description: Diazotrophy-related studies in the North Atlantic have largely focused on its western tropical area, leaving the subtropics and the east undersampled. We studied the longitudinal distribution of Trichodesmium , UCYN-A, UCYN-B, the putative Gammaproteobacterium -24774A11 and Richelia (Het1) along 24.5°N, using quantitative polymerase chain reaction on different size fractions (10, 10–3 and 3–0.2 µm) and additional filament counts for Trichodesmium. Trichodesmium was the most abundant phylotype, followed by UCYN-A, -24774A11 and Het1, with maximum abundances of 8.8 x 10 5 , 2.0 x 10 5 , 3.3 x 10 3 and 3.4 x 10 2 nifH copies L –1 , respectively, whereas UCYN-B was mostly undetected. A clear shift in the diazotroph community was observed at ~30°W, coinciding with the transition between the North Atlantic Subtropical Gyre boundary and inner core. This transition zone divided the transect into an eastern half dominated by UCYN-A and western half dominated by Trichodesmium and -24774A11. -24774A11 was only detected in the 10–3 µm fraction, suggesting their association with larger microbes or aggregates. Our results indicate that typical size fractionation by 10 µm is not optimal for reconciling diazotroph phylotypes to N 2 fixation rates and that non-cyanobacterial diazotrophs may contribute importantly to bulk diazotrophic activity in the western subtropical North Atlantic.
    Print ISSN: 0142-7873
    Electronic ISSN: 1464-3774
    Topics: Biology
    Published by Oxford University Press
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