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  • 1990-1994  (2)
  • 1994  (2)
  • Sperm competition  (1)
  • lectins  (1)
  • 1
    ISSN: 1432-0762
    Keywords: Mating tactics ; Paternity analysis ; Reproductive success ; Sperm competition ; Sorex araneus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The common shrew (Sorex araneus) is a solitary small mammal with a promiscuous mating system. Previous studies of this species suggest that females typically mate multiply, and that males may adopt alternative mate-searching tactics. We studied two generations of common shrews in a population near Oxford, England. Males were found to adopt two different mate-searching tactics. Those classed as type A occupied relatively small exclusive ranges during March, and made repeated long-distance movements to visit female ranges around the time of first oestrus in April. Males classed as type B established large overlapping ranges in areas of relatively high female density during March, and maintained these ranges throughout April. Type B males were larger than type A males at an early stage of sexual maturation, but there was no difference in the adult body size of the two types of male. Type A males had significantly higher epididymal sperm counts than type B males. Paternity analyses of litters born during the first year of the study reveal that the mean number of offspring fathered by type B males was greater than the mean number fathered by type A males. It is concluded that different mate-searching tactics may be conditional upon the timing of sexual maturation. Differences in sperm production are discussed in relation to sperm competition theory.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1573-4986
    Keywords: colon ; histochemistry ; lectins ; rectum ; ulcerative colitis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Ulcerative colitis is an idiopathic chronic inflammatory condition of the large bowel associated with åbnormalities of mucin synthesis and secretion. In the present study, glycans were identified in 45 formalin-fixed, paraffin-embedded tissue samples from patients with ulcerative colitis. The tissue samples represented a spectrum of inflammation from chronic quiescent disease to severe inflammation. Thirteen biotinylated lectins, directed against a range of sialyl, fucosyl andN-acetylgalactosaminyl sequences, were applied using an avidin-peroxidase revealing system. The results were assessed semiquantitatively for a number of cellular sites. The expression of all sialyl sequences was increased in absorptive cells and in goblet cells and the expression of α2–6-linked sialyl sequences was enhanced in proportion to the degree of inflammation, while α2–3-linked sialyl sequences were diminished in more severe inflammation. The binding ofN-acetylgalactosaminyl-directed lectins was increased in the Golgi apparatus, while there was a reduction in the expression of α-fucosyl sequences in severe degrees of inflammation. This suggests that there is an increased biosynthetic rate for sialyl residues in all stages of disease with a reduction in α2–3-linked sialyl and fucosyl sequences in severe inflammation, and a shift from storedN-acetylgalactosaminyl sequences in goblet cells to an earlier form in the Golgi apparatus. The changes in sialyl sequences are a feature of ulcerative colitis even in quiescent disease and may be related to its aetiology and early pathogenesis, while most of the other changes reflect the severity of the disease and are probably part of its later pathogenesis or of induced reactive changes.
    Type of Medium: Electronic Resource
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