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  • 11
    Electronic Resource
    Electronic Resource
    Phenolic metabolites of ecological significance in Empetrum hermaphroditum leaves and associated humus (1999)
    Springer
    Plant and soil 210 (1999), S. 1-9 
    Details
    ISSN: 1573-5036
    Keywords: batatasin-III ; boreal forest ; condensed tannins ; Empetrum hermaphroditum Hagerup ; humus composition ; phenolic acids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Condensed tannins, phenolic acids and batatasin-III were measured in green and senescent leaves of the dwarf Ericaceous shrub Empetrum hermaphroditum Hagerup collected at three boreal sites in northern Sweden. The influence of this shrub on the composition of soil phenolics was estimated through phenolic analysis of leaves and associated humus. Green leaves contained large amounts of batatasin-III (maximum value of 13.8 mg g-1 dry weight at one site) and condensed tannins (5.5 mg g-1), but lesser amounts of phenolic acids (1.7 mg g-1). All these compounds were also found in brown senescing leaves but at lower concentrations. Humus under E. hermaphroditum contained 1 μg g-1 of water-soluble batatasin-III and about 2 μg g-1 of water-soluble phenolic acids. When E. hermaphroditum was absent, batatasin-III was not recovered in humus and the concentration of phenolic acids was found to be much lower. We conclude that batatasin-III and some related metabolites (phenolic acids) could influence ecosystem function, because of their durability in E. hermaphroditum litter and humus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004699402687
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  • 12
    Electronic Resource
    Electronic Resource
    Pharmacodynamic effects of meropenem on gram-negative bacteria (1995)
    Springer
    European journal of clinical microbiology & infectious diseases 14 (1995), S. 383-390 
    Details
    ISSN: 1435-4373
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The in vitro initial killing and post-antibiotic effect (PAE) of meropenem on five gramnegative reference strains were evaluated by bioluminescence assay of bacterial adenosine triphosphate (ATP) and viable count. Morphology studies were performed in parallel. Meropenem showed concentration-dependent long (2–5 h) PAEs onEnterobacter cloacae, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa andSerratia marcescens when assayed by bioluminescence and induced spheroplasts at almost all concentrations. The bioluminescence PAEs reached a maximum response at 4 × MIC. These PAEs of meropenem onEscherichia coli, Klebsiella pneumoniae andSerratia marcescens were longer than corresponding PAEs of imipenem shown in previous studies. The higher affinity of meropenem than imipenem for PBP 3 might explain the longer PAEs obtained with meropenem. However, there was only a very short PAE, no PAE or even a negative PAE when viable count was used as the initial value for the PAE calculation. A strong initial decrease in viability but a less pronounced change in intracellular ATP was registered. Since this initial change in cell numbers is the initial value for the PAE calculation, the length of PAE was highly method dependent. In summary, a strong initial killing and no PAE were shown using viable count as the initial value for the PAE calculation, but a weak initial killing and long PAEs were shown when bioluminescence was used throughout the experiments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02114893
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  • 13
    Electronic Resource
    Electronic Resource
    Is citrate an inhibitor of calcium oxalate crystal growth in high concentrations of urine? (1996)
    Springer
    Urological research 24 (1996), S. 67-71 
    Details
    ISSN: 1434-0879
    Keywords: Calcium oxalate ; CaOx crystallization ; Crystal growth ; Inhibition ; Citrate ; Dialysed urine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effect of citrate on calcium oxalate (CaOx) crystal growth was studied in a system in which series of samples containing [45Ca]calcium chloride were brought to different levels of supersaturation with various concentrations of oxalate. The crystallization was assessed by measuring the amount of isotope remaining in solution 30 min after the addition of CaOx seed crystals to samples containing citrate in concentrations corresponding to those in final urine. The experiments were carried out both in pure salt solutions and in solutions with dialysed urine. Increased concentrations of citrate resulted in a reduced crystallization of CaOx in both the presence and absence of dialysed urine, but with the lowest rate of crystallization in the samples containing urine. The increased concentration of 45Ca remaining in solution reflected a reduced crystallization, which could possibly be explained both by a reduced supersaturation and by an increased inhibition of CaOx crystal growth. The direct effects of citrate on CaOx crystal growth were assessed by calculating the ion-activity product of CaOx (APCaOx) at corresponding degrees of crystallization. The APCaOx recorded at a 30% reduction of the amount of isotope in solution increased with increasing concentrations of citrate between 1.0 and 1.5 mmol/l in samples both with and without dialysed urine. These findings indicate that citrate has a weak direct inhibitory effect on CaOx crystal growth, which adds to the reduced growth rate brought about by urinary macromolecules and a decreased supersaturation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00431081
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  • 14
    Electronic Resource
    Electronic Resource
    Genetic diversity and classification of cyanobacteria in different Azolla species by the use of PCR fingerprinting (1999)
    Springer
    Theoretical and applied genetics 99 (1999), S. 1187-1193 
    Details
    ISSN: 1432-2242
    Keywords: Key words Azolla ; Cyanobacteria-Symbiosis ; Parsimony ; PCR-fingerprinting ; STRR
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Symbiotically associated cyanobacteria from 18 accessions within all known species in the genus Azolla were examined and classified by the use of polymerase chain reaction (PCR)-fingerprinting. A repetitive sequence specific for cyanobacteria, the short tandemly repeated repetitive (STRR) sequence, was used as a primer in the reaction. Cyanobacterial filaments isolated directly from the Azolla leaf cavity or contained within homogenised symbiotic Azolla tissue were used as templates. Based on the fingerprint pattern, distinct differences were demonstrated between cyanobacteria isolated from the Euazolla and Rhizosperma sections. In addition, individual fingerprints were obtained from all cyanobacteria isolated from the different Azolla species. The fingerprints were used to generate a phylogenetic tree. Three clusters were distinguished: one contained the four isolates from the section Euazolla, a second the isolate from Azolla filiculoides, and a third the three isolates from the section Rhizosperma. By the use of STRR-PCR fingerprinting, new data on the taxonomy of cyanobacteria in Azolla were obtained, which have been difficult to generate by other classification methods. PCR-fingerprinting may, therefore, be a valuable tool for diversity and classification studies of symbiotic cyanobateria from Azolla and, as co-evolution between the cyanobacteria and its corresponding host exists the method may also be useful for the taxonomy of Azolla.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001220051323
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  • 15
    Electronic Resource
    Electronic Resource
    Stable Isotope and Concentration Records of Atmospheric Lead Pollution in Peat and Lake Sediments in Sweden (1997)
    Springer
    Water, air & soil pollution 100 (1997), S. 243-252 
    Details
    ISSN: 1573-2932
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract We compare lead concentration and stable lead isotope analyses from three peat bog and three lake sediment records in Sweden. Radiocarbon dated stratigraphies give evidence that trends in the concentration of Pb in the peat and sediment cores are very similar, and follow the general outline of historical global Pb production over several thousand years. Due to the large difference in the 206Pb/207Pb ratio between Sweden, about 1.5, and continental Europe (excluding Fennoscandia), ≤1.2, it is possible to distinguish external sources of Pb to Sweden. In the lake sediments, profiles of 206Pb/207Pb ratio mirror the Pb concentration until 1000 AD; increasing concentration is accompanied by decreasing ratios. After 1000 AD the ratio varies little at about 1.2 in sediments, because of the near total dominance of pollutant Pb. There is a further decline in the Pb ratio to about 1.14 in this century as a result of the addition of alkyl-Pb in petrol. The Pb concentration profiles in the peat match the lakes, but the isotope profiles do not. During the fen-to-bog transition there is a rapid decline in the 206Pb/207Pb ratio from 〉1.3 to about 1.2, and the ratio continues to decline to the present. We hypothesise that this is because externally-derived Pb from long-range transport of soil dust and atmospheric pollution has always been more important in the ombrotrophic peat than in lakes, which have a greater influx of catchment-derived Pb.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018360106350
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  • 16
    Electronic Resource
    Electronic Resource
    Morphologic conversion ofHelicobacter pylori from bacillary to coccoid form (1996)
    Springer
    European journal of clinical microbiology & infectious diseases 15 (1996), S. 216-219 
    Details
    ISSN: 1435-4373
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The morphologic conversion ofHelicobacter pylori from bacillary to coccoid form was studied by microscopy, viable count on agar plates, and bioluminescence assay of bacterial ATP. When morphologic conversion from bacillary to coccoid form was detected by microscopy, the viable counts and the bacterial ATP decreased. No viable count was found after nine days of incubation, but bacterial ATP was still present. In these cultures in which only the coccoid form ofHelicobacter pylori was present, there was no accumulation of extracellular ATP, indicating no leaky cells. During the transition phase from the bacillary to the coccoid form ofHelicobacter pylori, the addition of fresh medium increased the intracellular ATP 26-fold. The coccoid form ofHelicobacter pylori had a 1000-fold lower ATP level per cell compared to the bacillary form, which indicates a decreased metabolic activity in the coccoid form. Addition of fresh medium to the coccoid cultures from days 9 and 10 increased the ATP level twofold. However, no conversion from coccoid to bacillary form was found in these cultures during prolonged incubation in fresh broth for four weeks. Such conversion needs to be demonstrated before it is proven that the coccoid form ofHelicobacter pylori is responsible for transmission and relapse of infection.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01591357
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  • 17
    Electronic Resource
    Electronic Resource
    The glycine antagonist (+)-HA-966 injected into the nucleus accumbens stimulates locomotion in mice (1997)
    Springer
    Journal of neural transmission 104 (1997), S. 419-425 
    Details
    ISSN: 1435-1463
    Keywords: (+)-HA-966 ; glycine ; NMDA ; mouse ; locomotion ; schizophrenia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We have previously observed that NMDA antagonists injected into the ventral striatum cause locomotor stimulation in both normal and monoamine-depleted mice. Since glycine receptor activation is claimed to be a prerequisite for NMDA receptor channel opening, also a glycine site antagonist injected into the ventral striatum should cause behavioural activation. The present study was aimed at investigating whether this is the case. The glycine site antagonist (+)-HA-966, as well as its (−)-enantiomer, were injected bilaterally into the nucleus accumbens of normal, habituated mice. (+)-HA-966, but not (−)-HA-966, was found to stimulate locomotion. The stereoselective response suggests that the underlying mechanism involves the NMDA receptor-coupled glycine site. The present results support the notion that a glycine agonist might be of value in the treatment of schizophrenia, whereas a glycine antagonist should be expected to have psychotogenic effects.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01277660
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