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  • 1
    ISSN: 1432-2242
    Keywords: Potato ; Dihaploid ; Parthenogenesis ; Fertilization ; Chromosome elimination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Seventeen potato dihaploids, produced by pollinating the tetraploid (2n = 48) cv ‘Pentland Crown’ with pollen from Solanum phureja (2n = 24) dihaploid inducer clones, were studied. Since dihaploids are thought to develop parthenogenetically from unfertilized ovules they were expected to be euploid (2n = 24), but somatic chromosome counts showed that 15 of the 17 dihaploids were aneusomatic. Ten of the clones were predominantly diploid (2n = 24) with a proportion of hyperploid cells that contained 25 or 26 chromosomes. Five of the dihaploids contained variable numbers of triploid cells (2n = 36). RFLP analysis was used to determine whether the additional chromosomes were from S. phureja or S. tuberosum. Unique hybridizing fragments present in S. phureja but not in ‘Pentland Crown’ were identified. These S. phureja-specific restriction fragments were present in some of the dihaploid offspring of ‘Pentland Crown’. Of the 5 clones that contained triploid cells 4 had S. phureja type banding. Four of the 10 aneusomatic clones that contained hyperploid cells had the unique S. phureja hybridizing fragments. We propose that ovules of ‘Pentland Crown’ were fertilized by pollen from S. phureja and that the aneusomatic clones were derived from triploid zygotes from which some of the S. phureja chromosomes were eliminated. We consider that this is an additional mechanism of dihaploid formation in potato.
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  • 2
    ISSN: 1432-2242
    Keywords: Key words  Brassica napus ; Cultivar identification ; DNA fingerprinting ; Anchored SSR ; PCR ; Silver staining
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract   Primers complementary to simple sequence repeats (SSRs) and with variable three-base `anchors' at their 5′ end, were used in PCR analyses to compare pooled DNA samples from various Brassica napus and B. rapa cultivars. Amplification products were resolved on polyacryl-amide gels and detected by silver-nitrate staining. The resulting banding patterns were highly repeatable between replicate PCRs. Two of the primers produced polymorphisms at 33 and 23 band positions, respectively, and could each discriminate 16 of the 20 cultivars studied. Combined use of both primers allowed all 20 cultivars to be distinguished. The UPGMA dendrogram, based on the cultivar banding profiles, demonstrated clustering on the basis of winter/spring growth habit, high/low glucosinolate content, and cultivar origin (i.e. the breeder involved). Intra-cultivar polymorphism was investigated using a minimum of ten individuals for each cultivar and was found to vary considerably between cultivars. It is concluded that anchored SSR-PCR analysis is a highly informative and reproducible method for fingerprinting oilseed rape populations, but that intra-cultivar variation should be investigated before using banding profiles from pooled samples for the identification of individuals.
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  • 3
    ISSN: 1432-2242
    Keywords: Key words Lupin ; Lupinus albus ; Germplasm collection ; ISSR-PCR ; Microsatellite ; Genebank
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The value of molecular biology for monitoring the genetic status of germplasm collections is subject to practical limitations. The large number and variability of accessions held usually dictates the approach that can be employed. A quick, simple but reliable molecular protocol must be combined with an appropriate strategy for handling large sample sizes. In this study, ISSR-PCR was used to reveal genetic variability within and between accessions held in a collection of lupin germplasm. Pooling of DNA from individuals within accessions was found to be the most appropriate strategy for assessing large quantities of plant material. Band profiles generated from pools containing five individuals were fully representative of all constituent individuals used in the mix. Pools comprising 10 or 20 individuals, however, sometimes failed to contain minor bands that had been present only in the profile of one individual. Variation was observed between pools containing five different genotypes from the same accession. Routine large-scale screens are required to assess the genetic diversity and homogeneity of the lupin germplasm collection held in Reading. It is concluded that 2–3 pools of five genotypes may be sufficient to represent the genetic variability within and between accessions in the lupin and similar collections.
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  • 4
    ISSN: 1432-2242
    Keywords: Key words DNA fingerprinting ; ISSR-PCR ; Solanum tuberosum ; Resolving Power
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Commercial scale fingerprinting of potato cultivars is made difficult by the need for speed, reliability and the ability to distinguish between large numbers of genotypes. There are also problems in extrapolating the results of small experimental studies to predict the performance of techniques or primers for larger applications. The potential of ISSR-PCR for fingerprinting purposes was evaluated using four primers on 34 potato cultivars. The complex band profiles generated were reproducible between repeat PCRs, DNA extractions, electrophoreses and gel scorings. Two primers were each able to distinguish all cultivars. The combined use of any two of the four primers also allowed complete diagnosis. It is concluded that ISSR-PCR provides a quick, reliable and highly informative system for DNA fingerprinting that is amenable for routine applications. Two possible correlates of the ability of primers to distinguish between genotypes were then examined. Marker Index failed to correlate significantly with genotype diagnosis, but a strong and seemingly linear relationship was observed between Resolving Power of a primer and its ability to distinguish genotypes (r2=0.98). Resolving Power of one or a pair of primers was found to provide a moderately accurate estimate of the number of genotypes identified. Possible implications for future studies on DNA fingerprinting are discussed.
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  • 5
    ISSN: 1432-2242
    Keywords: Brassica napus ; Cultivar identification ; DNA fingerprinting ; Anchored SSR ; PCR ; Silver staining
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Primers complementary to simple sequence repeats (SSRs) and with variable three-base ‘anchors’ at their 5′ end, were used in PCR analyses to compare pooled DNA samples from various Brassica napus and B. rapa cultivars. Amplification products were resolved on polyacrylamide gels and detected by silver-nitrate staining. The resulting banding patterns were highly repeatable between replicate PCRs. Two of the primers produced polymorphisms at 33 and 23 band positions, respectively, and could each discriminate 16 of the 20 cultivars studied. Combined use of both primers allowed all 20 cultivars to be distinguished. The UPGMA dendrogram, based on the cultivar banding profiles, demonstrated clustering on the basis of winter/spring growth habit, high/low glucosinolate content, and cultivar origin (i.e. the breeder involved). Intracultivar polymorphism was investigated using a minimum of ten individuals for each cultivar and was found to vary considerably between cultivars. It is concluded that anchored SSR-PCR analysis is a highly informative and reproducible method for fingerprinting oilseed rape populations, but that intra-cultivar variation should be investigated before using banding profiles from pooled samples for the identification of individuals.
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  • 6
    ISSN: 1432-2242
    Keywords: Key words Potato dihaploids ; Principal component analysis ; Dihaploid induction ; Microsatellite ; Isozyme analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A number of recent studies have provided evidence that potato dihaploids (S. tuberosum) contain and express DNA from the male (dihaploid inducer) parent, S. phureja. The importance of this for breeding programmes that use dihaploid potatoes is to some extent dependent upon whether the S. phureja DNA influences dihaploid morphology. In the present study, 21 characters were used to compare the morphology of six dihaploids with those of their parents: S. tuberosum (cvs `Pentland Dell' and `Pentland Crown') and S. phureja (IVP48). Characteristics of S. phureja were found in all of the dihaploids examined. In principal component analyses, dihaploids formed intermediate groupings positioned between those of the parents, although much closer to S. tuberosum. It is concluded there is evidence that DNA originating from the dihaploid inducer can affect the morphology of potato dihaploids. Implications of the findings are discussed.
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  • 7
    ISSN: 1434-3916
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary An in vivo histological and ultrastructural study of the cellular reaction to particulate material currently used in orthopaedic surgery produced evidence that, on a strictly cellular level, the main damage is done by the smallest particles produced by hip prostheses, i.e. metal particles, irrespective of differences in their chemical composition. Particle size and release rate are the critical factors, although other mechanisms of cellular damage may be active once granulation tissue is formed.
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  • 8
    ISSN: 1434-3916
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Von 4 gelockerten Hüftgelenktotalendoprothesen wurden die aus Metall und Polymer/Kunststoff bestehenden Implantate und das umgebende Gewebe untersucht. Bei allen Implantaten fanden sich ungewöhnlich reichlich Metallpartikeln, die durch Abrieb oder Korrosion des Femurstiels entstanden waren. Das Granulationsgewebe zwischen Knochen und Zement war charakterisiert durch Makrophagen, die Metallpartikeln enthielten. Es wurden histologische, histochemische und ultrastrukturelle Untersuchungen durchgeführt, um die zellulären Reaktionen auf die gespeicherten Metallpartikeln zu erfassen. Die Pathogenese der Lockerung in diesen Fällen wird in Zusammenhang mit der Rolle von Makrophagen bei der Knochenresorption diskutiert.
    Notes: Summary Four loosened metal-on-plastic total hip prostheses and associated tissues were examined. Each implant showed an uncommonly high formation of metal particles produced by wear or corrosion of the femoral stem. The granulation tissue between bone and cement was characterized by macrophages containing metal particles. Histological, histochemical, and ultrastructural investigations have been performed to assess cellular reactions to ingested metal particles. Pathogenesis of loosening in these cases is discussed in relation to the role of macrophages in bone resorption.
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  • 9
    ISSN: 1432-1955
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The mouse/Necator americanus model was studied to assess the histopathological changes that occur in the lungs following primary and secondary exposure to infective larvae. Groups of BALB/c mice were infected percutaneously and killed on various days post infection. Parasite numbers were counted, the bronchoalveolar leukocyte response was quantified and histological sections of lung material were examined for evidence of host protective inflammatory reactions. An increase in the inflammatory infiltration was observed between days 5 and 9 in both primary and secondary infections but was considerably more intense in re-infected animals. This involved a marked change in the character of the infiltrate, particularly in the number of eosinophils that were recovered in lavage fluid. More worms were trapped in the lungs of challenged mice, as assessed through their inability to escape from lung material incubated in vitro. Overall, the results were found to be compatible with the development of acquired resistance toN. americanus and the expression of host protective immunity during the development of challenge-infection larvae in the lungs.
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  • 10
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] SIR - Debate continues over the possible risks posed by transgene movement via pollen following the commercial release of genetically modified oilseed rape1'2. We have investigated the likelihood of glufosinate-tolerant transgenes first moving into and then influencing the survival of feral ...
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