E-cadherin-mediated cell-cell attachment activates Cdc42

E-cadherin is a transmembrane protein that mediates Ca(2+)-dependent cell-cell adhesion. Cdc42, a member of the Rho family of small GTPases, participates in cytoskeletal rearrangement and cell cycle progression. Recent evidence reveals that members of the Rho family modulate E-cadherin function. To further examine the role of Cdc42 in E-cadherin-mediated cell-cell adhesion, we developed an assay for active Cdc42 using the GTPase-binding domain of the Wiskott-Aldrich syndrome protein. Initiation of E-cadherin-mediated cell-cell attachment significantly increased in a time-dependent manner the amount of active Cdc42 in MCF-7 epithelial cell lysates. By contrast, Cdc42 activity was not increased under identical conditions in MCF-7 cells incubated with anti-E-cadherin antibodies nor in MDA-MB-231 (E-cadherin negative) epithelial cells. By fusing the Wiskott-Aldrich syndrome protein/GTPase-binding domain to a green fluorescent protein, activation of endogenous Cdc42 by E-cadherin was demonstrated in live cells. These data indicate that E-cadherin activates Cdc42, demonstrating bi-directional interactions between the Rho- and E-cadherin signaling pathways.     

A sensitive immunotransfer method for the detection of oligodendroglial plasma membrane antigens

Efficient transfer of a wide molecular weight range of plasma membrane proteins from polyacrylamide gels to nitrocellulose paper has been achieved. Using published immunodetection procedures (sensitivity: 1 ng protein), two major antigens of molecular weights of 71,000 and 82,000 have been identified in oligodendroglial plasma membranes. This immunotransfer method will be extremely useful for the detection of low levels of antigen in complex membrane protein mixtures.     

Visualization, modelling and prediction in soil microbiology

The introduction of new approaches for characterizing microbial communities and imaging soil environments has benefited soil microbiology by providing new ways of detecting and locating microorganisms. Consequently, soil microbiology is poised to progress from simply cataloguing microbial complexity to becoming a systems science. A systems approach will enable the structures of microbial communities to be characterized and will inform how microbial communities affect soil function. Systems approaches require accurate analyses of the spatio-temporal properties of the different microenvironments present in soil. In this Review we advocate the need for the convergence of the experimental and theoretical approaches that are used to characterize and model the development of microbial communities in soils.     

On the phytoscreening potential of insect-induced plant galls

Plant and Soil - Tussock microhabitat is a universal phenomenon in wetlands, where soil and plant properties differ from their surrounding lawns. This study aims to investigate the differences of...     

Monocytes Loaded with Indocyanine Green as Active Homing Contrast Agents?Permit Optical Differentiation of Infectious and Non-Infectious Inflammation

Distinguishing cutaneous infection from sterile inflammation is a diagnostic challenge and currently relies upon subjective interpretation of clinical parameters, microbiological data, and nonspecific imaging. Assessing characteristic variations in leukocytic infiltration may provide more specific information. In this study, we demonstrate that homing of systemically administered monocytes tagged using indocyanine green (ICG), an FDA-approved near infrared dye, may be assessed non-invasively using clinically-applicable laser angiography systems to investigate cutaneous inflammatory processes. RAW 264.7 mouse monocytes co-incubated with ICG fluoresce brightly in the near infrared range. In vitro, the loaded cells retained the ability to chemotax toward monocyte chemotactic protein-1. Following intravascular injection of loaded cells into BALB/c mice with induced sterile inflammation (Complete Freund’s Adjuvant inoculation) or infection (Group A Streptococcus inoculation) of the hind limb, non-invasive whole animal imaging revealed local fluorescence at the inoculation site. There was significantly higher fluorescence of the inoculation site in the infection model than in the inflammation model as early as 2 hours after injection (p<0.05). Microscopic examination of bacterial inoculation site tissue revealed points of near infrared fluorescence, suggesting the presence of ICG-loaded cells. Development of a non-invasive technique to rapidly image inflammatory states without radiation may lead to new tools to distinguish infectious conditions from sterile inflammatory conditions at the bedside.