Cisplatin induces modifications in the development of cell surface patterns of ciliates

Techniques and tools for species identification in ciliates: a review

Ciliates are highly divergent unicellular eukaryotic organisms with nuclear dualism and a highly specialized ciliary pattern. They inhabit all biotopes and play crucial roles in regulating microbial food webs as they prey on bacteria, protists and even on microscopic animals. Nevertheless, subtle morphological differences and tiny sizes hinder proper species identification for many ciliates. In the present review, an attempt has been made to elaborate the various approaches used by modern day ciliate taxonomists for species identification. The different approaches involved in taxonomic characterization of ciliates such as classical (using live-cell observations, staining techniques, etc.), molecular (involving various marker genes) and statistical (delimitation of cryptic species) methods have been reviewed. Ecological and behavioural aspects in species identification have also been discussed. In present-day taxonomy, it is important to use a ‘total evidence’ approach in identifying ciliates, relying on both classical and molecular information whenever possible. This integrative approach will help in the mergence of classical methods with modern-day tools for comprehensive species description in future.

Down-Regulation and Altered Localization of γ-Catenin in Cisplatin-Resistant Adenocarcinoma Cells

Resistance to cisplatin, one of the most widely used anticancer chemotherapeutic agents, is a major clinical problem. There is no effective way to predict development of cisplatin resistance in cancers. As determined by reverse transcription-polymerase chain reaction and Western blotting, the expression of gamma-catenin, an adherens junction protein, was decreased in KB-CP20 and 7404-CP20 cells compared with parental-sensitive cells. Short-term treatment with cisplatin of the parental cells resulted in proteolysis of gamma-catenin as evaluated in membrane pellet preparations, and the extent of cleavage increased as cisplatin concentration was raised from 1 to 5 microg/ml during 1 h of treatment. Uncleaved cytoplasmic gamma-catenin increased under the same conditions. These biochemical results were supported by confocal microscopy, which showed a loss of gamma-catenin from adherens plaques after cisplatin treatment. Cleavage of gamma-catenin was specific to cisplatin treatment in that cleavage did not occur after treatment with doxorubicin and cytosine arabinoside. Pretreatment of KB and 7404 cells with cisplatin for 1 h resulted in reduced uptake of [(14)C]carboplatin, suggesting that the biochemical changes induced by cisplatin treatment, including cleavage of gamma-catenin, could affect the ability of cells to internalize platinum compounds. Cells transfected with the gamma-catenin gene are sensitive to cisplatin compared with cells transfected with a control vector. Our data suggest that proteolysis and altered localization of gamma-catenin are early markers for the response of cells to cisplatin, and reduced levels of gamma-catenin in resistant cells may indicate an important role for gamma-catenin in mediating or modulating the toxicity of cisplatin in cancer cells.