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  • Articles  (75)
  • Springer  (75)
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  • Articles  (75)
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  • 1
    Electronic Resource
    Electronic Resource
    Diagnostic and therapeutic applications of azulenyl nitrone spin traps (1999)
    Springer
    Cellular and molecular life sciences 56 (1999), S. 626-633 
    Details
    ISSN: 1420-9071
    Keywords: Key words. Azulenyl nitrones; azulenes; nitrones AZN; PBN; S-PBN; free radicals; spin traps; antioxidants; neuroprotection; oxidative stress; assay; amyotrophic lateral sclerosis; FALS; superoxide dismutase; transgenic mice; stroke; ischemia/reperfusion; Parkinson’s disease; MPTP; axotomy; neurodegeneration.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Azulenyl nitrones have been recently demonstrated to constitute a new class of nitrone-based spin traps with the unprecedented capacity to tag free radicals by yielding characteristically colored and highly visible diamagnetic (and paramagnetic) spin adducts. In addition, a comparison of the oxidation potentials of azulenyl nitrones such as 1 and congeners to those of conventional nitrone spin traps previously investigated as potential antioxidant therapeutics such as N-tert-butyl-α-phenylnitrone and its related ortho-sodium sulfonate reveals that the azulene-derived spin traps are far more readily oxidized. These special features render azulenyl nitrones of interest with regard to both their distinct ability to engender the convenient use of colorimetric detection to monitor free radical-mediated oxidative stress in biological systems, and to their potentially enhanced efficacy as neuroprotective antioxidants vs. those conventional nitrone spin traps earlier examined as such. Herein is reported an overview of recent developments pertaining to the use of azulenyl nitrones in the detection of oxidative stress in animal models of amyotrophic lateral sclerosis and stroke, and to their neuroprotective activity in animal models of Parkinson’s disease, stroke and neurodegeneration within the retina.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s000180050457
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  • 2
    Electronic Resource
    Electronic Resource
    Promoters derived from banana bunchy top virus DNA-1 to −5 direct vascular-associated expression in transgenic banana (Musa spp.) (2000)
    Springer
    Plant cell reports 19 (2000), S. 810-814 
    Details
    ISSN: 1432-203X
    Keywords: Key words Banana bunchy top virus ; Promoter ; Vascular expression ; Green fluorescent protein ; Intron-mediated enhancement
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The intergenic regions of banana bunchy top virus (BBTV) DNA-1 to -5 were fused to the green fluorescent protein (GFP) and uidA reporter genes and assessed for promoter activity in transgenic banana (Musa spp. cv. Bluggoe). Promoter activity associated with the BBTV-derived promoters was transgene dependent with greatest activity observed using the GFP reporter. The BBTV promoters (BT1 to BT5) directed expression primarily in vascular-associated cells, although levels of activity varied between individual promoters. Promoters BT4 and BT5 directed the highest levels of GFP expression, while activity from BT1, BT2 and BT3 promoters was considerably weaker. Intron-mediated enhancement, using the maize polyubiquitin 1 (ubi1) intron, generated a significant increase in GUS expression directed by the BBTV promoters in transgenic plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002999900185
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  • 3
    Electronic Resource
    Electronic Resource
    Cyclisches Adenosin-3′:5′-monophosphat in pflanzlichen Leitbahnen? (1973)
    Springer
    Planta 110 (1973), S. 85-89 
    Details
    ISSN: 1432-2048
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Sieve tube sap of the secondary phloem of Robinia pesudoacacia L. and exudate from the trumpet hyphae of the cauloids of Laminaria saccharina (L.) Lamour. were analyzed for the occurrence of cyclic adenosine-3′:5′-monophosphate with the help of the radio isotope dilution test (Boehringer, Mannheim). The concentration was about 0,1 μM in the Laminaria exudate and 9,0 nM in the Robinia sap. Pretreatment of the saps with phosphodiesterase removes the activity of the A-3:5-MP. It therefore seems probable that A-3:5-MP occurs in the translocation tissues of plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00386927
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  • 4
    Electronic Resource
    Electronic Resource
    Inward rectifier potassium channels in plants differ from their animal counterparts in response to voltage and channel modulators (1995)
    Springer
    European biophysics journal 24 (1995), S. 107-115 
    Details
    ISSN: 1432-1017
    Keywords: Potassium channel ; KAT1 ; Voltage dependence ; Cesium block ; pH dependence ; Kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract We have investigated the electrophysiological basis of potassium inward rectification of the KAT1 gene product from Arabidopsis thaliana expressed in Xenopus oocytes and of functionally related K+ channels in the plasma membrane of guard and root cells from Vicia faba and Zea mays. The whole-cell currents passed by these channels activate, following steps to membrane potentials more negative than −100 mV, with half activation times of tens of milliseconds. This voltage dependence was unaffected by the removal of cytoplasmic magnesium. Consequently, unlike inward rectifier channels of animals, inward rectification of plant potassium channels is an intrinsic property of the channel protein itself. We also found that the activation kinetics of KAT1 were modulated by external pH. Decreasing the pH in the range 8.5 to 4.5 hastened activation and shifted the steady state activation curve by 19 mV per pH unit. This indicates that the activity of these K+ channels and the activity of the plasma membrane H+-ATPase may not only be coordinated by membrane potential but also by pH. The instantaneous current-voltage relationship, on the other hand, did not depend on pH, indicating that H+ do not block the channel. In addition to sensitivity towards protons, the channels showed a high affinity voltage dependent block in the presence of cesium, but were less sensitive to barium. Recordings from membrane patches of KAT1 injected oocytes in symmetric, Mg2+-free, 100 mM-K+, solutions allowed measurements of the current-voltage relation of single open KAT1 channels with a unitary conductance of 5 pS. We conclude that the inward rectification of the currents mediated by the KAT1 gene product, or the related endogenous channels of plant cells, results from voltage-modulated structural changes within the channel proteins. The voltage-sensing or the gating-structures appear to interact with a titratable acidic residue exposed to the extracellular medium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00211406
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  • 5
    Electronic Resource
    Electronic Resource
    Zur Berechnung statistisch schwankender Impulsfolgen und ihrer Überlagerung (1966)
    Springer
    Biological cybernetics 3 (1966), S. 191-196 
    Details
    ISSN: 1432-0770
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Computer Science , Physics
    Notes: Summary In the central nervous system information transmission and processing are accomplished by pulses and pulse trains. The superposition of pulse trains is essential for information processing as it allows the execution of several logical operations, e.g. the multiplication of afferent signals. Jenik (1961) has pointed out that for the superposition of periodic pulse trains the rate of coincidence is proportional to the product of the pulse repetition frequencies (“multiplication law“). Furtheron he has shown that this simple principle is not always applicable. Errors may occur for certain repetition frequencies of the pulse trains. If the product of signals is accomplished by superposition, mechanisms must exist reducing these errors. Since pulse trains in the nervous system always vary stochastically the following paper is concerned with the effect of random pulse trains in superposition. Two different types of random pulse trains are investigated, trains with random phase and trains with random interval between the pulses. For these two cases calculation methods are given. It is also shown that the deviations from the “multiplication law” may disappear when superimposing random pulse trains.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00290256
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  • 6
    Electronic Resource
    Electronic Resource
    Linkage mapping and QTL analysis in coconut (Cocos nucifera L.) (2000)
    Springer
    Theoretical and applied genetics 101 (2000), S. 292-300 
    Details
    ISSN: 1432-2242
    Keywords: Key words AFLP ; DNA markers ; Early germination ; ISSR ; ISTR ; RAPD
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Different DNA marker types were used to construct linkage maps in coconut (Cocos nucifera L.; 2n = 32) for the two parents of the cross Malayan Yellow Dwarf (MYD) × Laguna Tall (LAGT). A total of 382 markers was sufficient to generate 16 linkage groups for each parent. The total genome length corresponded to 2226 cM for the LAGT map and 1266 cM for the MYD map with 4–32 markers per linkage group. Common markers allowed the association of 9 linkage groups for the two parents MYD and LAGT. QTL analysis for the trait early germination identified six loci. These QTLs correlate with early flowering and yield, representing characters which are important in coconut breeding. The co-segregation of markers with these QTLs provides the first opportunity for marker-assisted selection in coconut breeding programmes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001220051482
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  • 7
    Electronic Resource
    Electronic Resource
    Grain-boundary deformation behaviour in a metastable beta-titanium alloy (1981)
    Springer
    Journal of materials science 16 (1981), S. 2031-2035 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00540660
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  • 8
    Electronic Resource
    Electronic Resource
    Sex pheromone components of the giant looper,Boarmia selenaria schiff. (Lepidoptera: Geometridae): Identification, synthesis, electrophysiological evaluation, and behavioral activity (1992)
    Springer
    Journal of chemical ecology 18 (1992), S. 165-181 
    Details
    ISSN: 1573-1561
    Keywords: Boarmia selenaria ; giant looper ; sex pheromones ; Lepidoptera ; Geometridae ; (Z,Z)-6,9-cis-(3S,4R)-epoxynonadecadiene ; (Z,Z)-6,9-cis-(3R,4S)-epoxynonadecadiene ; (Z,Z,Z)-3,6,9-nonadecatriene, anantiomers ; enantioselective synthesis ; EAG ; wind tunnel ; field tests ; precursor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract (Z,Z)-6,9-cis-(3S,4R)-Epoxynonadecadiene9a and (Z,Z,Z)-3,6,9-nonadecatriene have been identified as sex pheromone components in female ovipositor extracts and effluvia of the geometridBoarmia selenaria. The identification was based on relative retention times on gas chromatographic columns, GC-MS, chemical enantioselective syntheses, EAG, wind-tunnel behavioral experiments, and field tests. A single female ovipositor extract contained an average of 42 ng of (Z,Z)-6,9-cis-3,4-epoxynonadecadiene and 2 ng of (Z,Z,Z)-3,6,9-nonadecatriene.EAG, wind-tunnel behavioral studies, and field tests demonstrated that maleB. selenaria exhibit preferential attraction for the (3S,4R)-enantiomer of (Z,Z)-6,9-cis-3,4-epoxynonadecadiene. Only in effluvia and ovipositor extracts of calling females was (Z,Z)-6,9-cis- 3,4-epoxynonadecadiene detected, whereas relatively high amounts of (Z,Z,Z)-3,6,9-nonadecatriene were found in noncalling females. Wind-tunnel behavioral studies showed that (Z,Z,Z)-3,6,9-nonadecatriene did not elicit any response in the males, and when tested in combination with a mixture of monoepoxynonadecadienes, (Z,Z,Z)-3,6,9-nonadecatriene decreased the observed behavioral responses. A possible precursor role for (Z,Z,Z)-3,6,9-nonadecatriene in the pheromonal system is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00993751
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  • 9
    Electronic Resource
    Electronic Resource
    Distribution of mercury in the aquatic food web of Onondaga Lake, New York (1995)
    Springer
    Water, air & soil pollution 80 (1995), S. 563-571 
    Details
    ISSN: 1573-2932
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Historical discharges of mercury (Hg) to Onondaga Lake, New York, have resulted in elevated Hg concentrations in lake fishes. In 1990, a remedial investigation and feasibility study (RI/FS) was initiated to evaluate problems related to Hg and other hazardous substances in the lake. As part of the RI/FS, the distribution of Hg in the aquatic food web was determined to provide input to a site-specific model of Hg cycling and to evaluate potential ecological risks of Hg in the lake. Mercury concentrations were measured in surficial sediments, sediment interstitial water, lake water, phytoplankton, Zooplankton, benthic macroinvertebrates, and fishes (including planktivores, benthivores, and piscivores). The percentage of total Hg accounted for by methyl-Hg (CH3Hg) generally increased with higher trophic levels, confirming that CH3Hg is more efficiently transferred to higher trophic levels than is inorganic Hg. Concentrations of total Hg in amphipods and chironomids were closely related to concentrations of total Hg in sediments, suggesting that sediments are a likely source of Hg for benthic macroinvertebrates. Mercury concentrations in edible muscle tissue (fillets) of lake fishes have declined substantially from values found in the early 1970s, reflecting the large reductions in Hg discharges to the lake that have occurred since that time. The CH3Hg concentrations in fillets and whole bodies of fishes generally were similar, indicating that concentrations in fillets often can provide estimates of concentrations in whole bodies. Methyl-Hg concentrations and bioaccumulation factors increased with higher trophic levels in both the pelagic and benthic components of the lake food web.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01189706
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  • 10
    Electronic Resource
    Electronic Resource
    High-yielding repetitive somatic embryogenesis and plant recovery in a selected tea clone, ‘TRI-2025’, by temporary immersion (2000)
    Springer
    Plant cell reports 19 (2000), S. 1140-1145 
    Details
    ISSN: 1432-203X
    Keywords: Keywords Multiplication ; TIS ; Propagation ; ¶Secondary embryogenesis ; Tissue culture ; Regeneration ; AbbreviationsSEM Somatic embryos ; PGR Plant growth regulators ; TIS Temporary immersion system
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Methods for improving the efficiency of repetitive somatic embryogenesis and plant recovery from somatic embryos of clonal tea, TRI 2025 [Camellia sinensis (L.) O. Kuntze] were investigated by optimising the immersion frequencies of the explants using a modified temporary immersion system (TIS). The relative efficiencies of three conventional methods for multiplying embryos were compared with the temporary immersion method. The highest rate of multiplication of secondary embryos (24-fold) was achieved using the TIS. By controlling the immersion cycles, we achieved more consistent, synchronised multiplication and embryo development with a high level of plant recovery. A one-step computer-programmed immersion protocol based on a single, simple medium with no growth regulators was developed, enabling multiplication, maturation, germination and plant recovery within 17 weeks. Plantlets recovered through this method were hardy, with 2- to 5-cm-long shoots containing a minimum of 2–4 lush green leaves and a well-formed taproot. Callus formation, hyperhydricity and other developmental abnormalities were not observed at any stage in the process. Plantlets produced using this method were successfully acclimatised to glasshouse conditions. This protocol avoids culture transfers, and thus minimises the risk of contamination and reduces labour costs. This technique could have significant commercial implications in tea propagation as it has the potential for large-scale production with considerably reduced production costs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002990000239
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