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  • 1
    ISSN: 1573-2657
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The main objective of this study was to analyse glycogen in single muscle fibres, using a recently developed microfluorometric method which detects subpicomol amounts of NADPH, glucose and glycogen (as glucosyl units) (detection limit 0.16–0.17pmol in a 25nl sample) without fluorochrome amplification. The fibres were freshly dissected from the twitch region of the iliofibularis muscle of the cane toad (Bufo marinus), and were mechanically skinned under paraffin oil to gain access to the intracellular compartments. The results show that: (1) glycogen concentrations in toad skeletal muscle fibres range between 25.8 and 369mmol glucosyl units/litre fibre volume; (2) there is a large variation in glycogen content between individual fibres from the iliofibularis muscle of one animal; (3) there are seasonal differences in the glycogen content of toad single muscle fibres; (4) the total amount of glycogen in single muscle fibres of the toad does not decrease significantly when storing the tissue, under paraffin oil, at 20–25°C for up to 6h or at 4°C for up to 24h; and (5) 15–26% of fibre glycogen can be washed in an aqueous solution at pH 5–7, within 5min, while 74–85% of fibre glycogen remains associated with the washed skinned fibre, even after 40min exposure of the skinned fibre preparation to the aqueous environment. The retention of most glycogen in the fibre preparation after mechanical removal of the plasma membrane and extensive washing indicates that in toad skeletal muscle fibres the largest proportion of glycogen is tightly bound to intracellular structures. The results also show that the skinned muscle fibre preparation is well suited for microfluorometric glycogen determination, since low molecular weight non-glycogen contributors to the fluorescence signal can be removed from the myoplasmic space prior to the glycogen hydrolysis step.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0630
    Keywords: PACS: 68.55; 72.20; 81.10
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-0894
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract  The total ozone column is well correlated with tropospheric fields such as the heights of the upper tropospheric geopotential surfaces and thus it can provide useful information on temporal variability in the troposphere. The global availability of long period satellite measurements of the total ozone column, taken by the TOMS instruments since 1978, provides a valuable and independent data set for use in studies of seasonal and interannual climate variability. In this study, the global low-frequency seasonal teleconnections in the observed TOMS data from 1979–91 have been investigated using seasonal teleconnectivity maps and empirical orthogonal function analysis. They have also been compared with the results from a simulation made with the atmospheric GCM at Météo-France, having prescribed observed sea surface temperatures for the same period. In the observed total ozone, strong ENSO-related wave number one longitudinal dipole patterns are seen in both the tropics and in the Southern Hemisphere extratropics. The model shows much weaker variability in total ozone yet appears to be able to capture similar teleconnection patterns in the tropics related to ENSO. In the SH extratropics, the model total ozone shows a strong wave number 3 response rather than the wave number one dipole seen in the observations. A wave number 3 response is also evident in the 200 hPa geopotential height simulated by the model and in the NCEP analysis, and is consistent with the response in a linearised barotropic model forced in the Indonesian region. The different responses in the modelled and observed total ozone, suggest that tropopause effect is not the major factor in the SH extratropics, and it is likely that horizontal ozone transport also plays a role in this region. Despite a generally poor simulation of the zonal mean total ozone, the model was able to capture the anomalous strengthening of the SH stationary waves during austral spring of 1988, related to an intense stratosphere sudden warming.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-2145
    Keywords: Key words Cucurbita ; Pollen tube growth ; Pollen performance ; Hybridization ; Variation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  This study examines sporophytic and gametophytic vigor in wild and cultivated varieties of Cucurbita pepo L. and their hybrids in order to determine whether hybrid vigor extends to the microgametophyte generation. It also examines the variation in sporophytic and gametophytic vigor to discern the non-genetic influences of pollen provisioning by the sporophyte on pollen performance from the genetic influences of the microgametophyte’s own genotype on pollen performance. A cultivated and a wild C. pepo and their F1 and the F2 generations were grown under field conditions and flower and fruit production were monitored over one summer. We found that the four types of plants differed significantly in the number of male and female flowers and the number of fruits they produced. The F1 plants produced significantly more male flowers and marginally more female flowers and fruits than the parental lines. To estimate gametophytic vigor pollen was germinated in vitro and pollen tube length measured after 30 min. We found that pollen tubes from the F1 plants had significantly greater growth than tubes from the parental lines or the F2 generation, indicating that hybrid vigor extends to the microgametophytic generation. By partitioning the variance of pollen tube growth into ’within’ and ’among’ plant components of variation, we were able to show that the genotype of the microgametophyte influences pollen performance in vitro, but that expression of hybrid vigor in the microgametophyte is likely to be due to an environmental effect related to provisioning of the pollen grains during development.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 97 (1998), S. 946-949 
    ISSN: 1432-2242
    Keywords: Key words Wheat ; Microsatellite markers ; Genetic map
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Hexaploid bread wheat (Triticum aestivum) has low levels of RFLP. Simple sequence repeats, however, show high levels of polymorphism and are therefore especially useful in intervarietal breeding applications. We present 53 newly mapped microsatellite loci for the wheat genetic map, 41 primary loci and 12 additional loci from these same primer pairs. Markers have been accredited with a quality score on a scale of 1–5 which describes the complexity of the amplification product profile from each primer pair.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1435-0653
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Meloidogyne arenaria (Neal) Chitwood race 1] causes significant economic losses throughout the peanut (Arachis hypogaea L.) production areas of the southern USA. No resistant peanut cultivars are available; however, a breeding line (UF81206) has been observed to be less sensitive to M. arenaria than commercial cultivars. The objectives of this study were to evaluate the sensitivity to M. arenaria of UF81206 and related breeding lines and to determine if these responses are due to tolerance, or resistance. The yield of 10 peanut genotypes was evaluated for 2 yr in a field with high M. arenaria population densities and in a field with little or no M. arenaria. Two greenhouse tests were conducted to measure nematode reproduction. The breeding lines UF81206-Q4, UF81206, and UF93111 yielded similarly to Florunner when grown in fields with no nematodes and significantly higher than Florunner when grown in fields with high nematode population densities. These genotypes also supported less nematode reproduction in greenhouse trials, indicating that these genotypes have a moderate level of resistance. P1203396 is in the pedigree of these breeding lines and also exhibited a moderate level of resistance in a greenhouse trial.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Genetic resources and crop evolution 45 (1998), S. 415-421 
    ISSN: 1573-5109
    Keywords: barley ; diversity ; microsatellites ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Microsatellite (SSR) profiles from 65 wheats and 135 barleys have been generated, involving 14 and 22 loci, respectively. The wheat and barley varieties were chosen to represent the bulk of the area sown to these crops in the UK over the past 70 years. The profiling identified genotypic mixtures in some seed samples. Null alleles were common in wheat, but rare in barley. We describe attempts to increase the efficiency of data acquisition. High resolution agarose gel electrophoresis was unable to satisfactorily resolve 1–2 repeat unit differences in the common size range for SSR loci, and was therefore unsuitable for mass screening of allelic variants. Multiplex PCR was very dependent on the choice of primer combinations and seldom produced amplifications as consistently as when primer pairs were used individually. Background (non-specific) amplification was common to many primer pairs, and this hindered the use of both multiplex PCR and multiple sample loading. Sequential sample loading was the most effective strategy, although this was the least time-efficient of the measures used.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1573-0603
    Keywords: Adhesin ; Antibody ; Bacteria ; Fab ; Phage display
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Surface proteins provide a multitude of functions for the bacterial cell. Antibodies to these proteins can provide tools for tagging bacteria and characterizing protein function. Phage display technology has emerged as a powerful method for producing monoclonal Fabs in Escherichia coli. In an effort to study the adhesion mechanisms of Streptococcus parasanguis FW213, Fabs specific for the surface adhesin protein Fap1 were produced using phage display. The immune repertoire of a mouse injected with purified Fap1 was cloned into the phagemid vector pCOMB3, and a combinatorial Fab library was expressed in E. coli. A cell-based panning method using whole S. parasanguis cells was developed and has been shown to be a means for enriching for Fabs specific for the Fap1 protein.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 33 (1998), S. 5131-5136 
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The influence of supersolidus liquid phase sintering (SLPS) on the density of sintered components manufactured using a Ni-base superalloy powder (N18) has been studied. A compression moulding technique was employed to simulate the metal injection moulding (MIM) process using coarse N18 powder, with a particle size distribution of 40–63 μm, as opposed to fine powders of less than 10μm normally used in conventional MIM. The study has demonstrated how the problem of low sintered density, encountered in solid-state sintering using coarse powders, can been overcome by SLPS and that the sintered densities of the N18 powder via the moulding process route were comparable with those produced by conventional die pressing and sintering.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 17 (1998), S. 377-379 
    ISSN: 1573-4811
    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
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