Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    ISSN: 1432-0983
    Keywords: Key wordsPhysarum polycephalum ; Mitochondrial DNA ; Plasmodial senescence ; Single-stranded breakage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We found that mitochondrial DNA (mtDNA) isolated from Physarum polycephalum fragmented itself in weak ionic solutions. The mtDNA was dissolved in STE (saline Tris-EDTA: 150 mM NaCl, 10 mM Tris-HCl, 1 mM EDTA), TE (10 mM Tris-HCl, 1 mM EDTA) and DW, and then electrophoresed in an agarose gel. The intact 86-kbp mtDNA band was seen in STE, but several novel bands appeared in TE and DW. In TE, two discrete bands appeared at 6.7-kbp (α-band) and 5.0-kbp (β-band), whereas at least 17 discrete bands were observed in distilled water (DW). These fragmentation patterns were not stoichiometric, as seen when using restriction endonucleases, but were clearly different from the degradation of DNA caused by a physical shearing force or a contaminating nuclease. In this paper, we characterize this in vitro fragmentation of mtDNA from P. polycephalum. We located 19 fragments, including the α and β fragments, on a mtDNA restriction map, and demonstrated that these cleavage sites were S1 nuclease-sensitive regions, which are single-stranded DNA regions such as nicks and gaps in the mtDNA. The α and β fragments are derived from the region encoding ribosomal RNAs (rRNAs) and the ATP synthase (atpA) gene, while the other 17 fragments are not derived from any specific region, but the cleavage sites are located throughout the mtDNA molecule. In P. polycephalum, it is well known that the growth rate of macroplasmodia decreases with aging. Equal amounts of mtDNA from juvenile and aged macroplasmodia were electrophoresed and the frequency of the β fragment in each sample was measured. The ratio of the β band to the total signal including background was estimated to be 3.3–4.0% in juvenile macroplasmodia, whereas it increased to 8.3–28.2% in aged macroplasmodia. This result suggests that the in vitro fragmentation of mtDNA is associated with macroplasmodial senescence. The single-stranded breakage of mtDNA of P. polycephalum may accumulate with age.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1573-2568
    Keywords: DIVERTICULA ; PARADIVERTICULITIS ; HEMORRHAGE ; FECAL OCCULT BLOOD ; COLONOSCOPY
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Colonic diverticula have been generally acceptedas a source of massive hemorrhaging. Little is known,however, about fecal occult blood loss from colonicdiverticula and diverticulosis. We retrospectively investigated the possibility of minor bleedingin 737 diverticula cases diagnosed from April 1989 toMay 1994. Thirty-seven cases (5%) of diverticula areexplained as the sources of positive occult blood testing ascertained clearly by colonoscopy.These divide into three types: (1) fromintradiverticular bleeding (intradiverticulitis), (2)from peridiverticular bleeding (peridiverticulitis), and(3) from interdiverticular colonic mucosal erosion(interdiverticulitis). These findings account for theoccult blood loss that we call paradiverticulitis. Thetwo-year prospective study found 67 cases (11.3%) of paradiverticulitis in 595 diverticula cases.We concluded that paradiverticulitis is one of thecauses of positive occult blood tests.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...