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
Filter
  • 2000-2004  (2)
  • 1995-1999
  • 1965-1969
  • 1960-1964
  • 1945-1949
  • 1925-1929
  • 2004  (2)
Material
Years
  • 2000-2004  (2)
  • 1995-1999
  • 1965-1969
  • 1960-1964
  • 1945-1949
  • +
Year
  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Molecular microbiology 51 (2004), S. 0 
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: The small G-protein superfamily is an evolutionarily conserved group of GTPases that regulate diverse signalling pathways including pathways for growth and development in eukaryotes. Previously, we showed that dominant active mutation in the unique Ras gene (DARas) of the fungal phytopathogen Colletotrichum trifolii displays a nutrient-dependent phenotype affecting polarity, growth and differentiation. Signalling via the MAP kinase pathway is significantly impaired in this mutant as well. Here we describe the cloning and functional characterization of Rac (Ct-Rac1), a member of the Rho family of G proteins. Ct-Rac1 expression is downregulated by DARas under limiting nutrition. Co-expression of DARas with dominant active Rac (DARac) stimulates MAPK activation and restores the wild-type phenotype. Inhibition of MAPK activation suppresses phenotypic restoration suggesting Rac-mediated MAPK activation is responsible for reversion to the wild-type phenotype. We also examined the role of reactive oxygen species (ROS) in these genetic backgrounds. The DARas mutant strain generates high levels of ROS as determined by DCFH-DA fluorescence. Co-expression with DNRac decreases ROS generation to wild-type levels and restores normal fungal growth and development. Pretreatment of DARas with antioxidants or a cytosolic phospholipase A2 inhibitor also restores the wild-type phenotype. These findings suggest that Ras-mediated ROS generation is dependent on a Rac–cPLA2-linked signalling pathway. Taken together, this study provides evidence that Rac functions to restore the hyphal morphology of DARas by regulating MAPK activation and intracellular ROS generation.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1365-2559
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Aims : The World Health Organization classification of bronchial intraepithelial neoplastic lesions has been shown to be reproducible. However little is known about its biological value. The aim of this study was to assess the proliferative activity of mild (MiD), moderate (MoD), severe (SD) dysplasia and carcinoma in situ (CIS) by the expression of Ki67 on biopsy specimens obtained during fluorescence bronchoscopy.Methods and results : The percentage of Ki67+ lesional nuclei was calculated in each lesion. In addition, the presence of Ki67 clusters (defined as a group of at least two strongly Ki67+ nuclei located in the upper third of the epithelium) and a Ki67 score were evaluated. The Ki67 score depended on the proportion of the stained nuclei and on the intensity of staining. MiD, MoD, SD and CIS showed increased Ki67 staining (respectively, 10%, 20%, 30% and 40% median values of positive cells). Thirty-one percent MiD, 77% MoD, 91% SD and 100% CIS showed one or more positive clusters. When only multiple clusters were considered the difference between high- and low-grade lesions was accentuated. Ki67+ clusters were more frequent in SD (91%) and CIS (94%) compared with MiD (15%) and MoD (22%). This difference was statistically significant (P 〈 0.01). Evaluation of the Ki67 score was in line with the above results: high grade lesions (SD and CIS) more often showed scores 〉4 (P = 0.05 between MiD plus MoD versus SD plus CIS).Conclusions : Ki67 expression increases from MiD to CIS with a statistically significant difference between MiD plus MoD and SD plus CIS. These results suggest that, in terms of Ki67 positivity, SD behaves like CIS rather than like MiD or MoD.
    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...