Cluster analysis of Anopheles Stephensi fourth instar larvae behavior to explore sequential organisation of larvae movement in a microcosm

Experiments were conducted on 20 fourth instar Anopheles stephensi larvae to explore behavior organisation. Twenty fourth instar larvae were placed in a glass aquarium and filmed using a handy cam video recorder and the recordings analysed in a laptop computer. Data of transitions from one behavior to another for all observations were collated into a matrix of preceding and succeeding behaviors to study sequential organisation and relationship among behaviors. Significant testing for first-order transition was done using G test at P< 0.005 and a kinematic graph constructed from significant transitions. A time budget and transition frequency data constructed for each behavior were subjected to cluster analysis to explore relationship between the behaviors. Result of the analysis showed that fourth instar Anopheles stephensi larvae behaviors occur in clusters in specific locations in their aquatic environment. Furthermore, the sequential organisation of behaviors is influenced by behavior frequency and the amount time a larva spent doing that behavior. When food is kept constant, other factors such as gas exchange requirements, behavior variation due to day-night cycle, presence of a predator, interlarval competition for food and the size of the aquarium (depth and width) maybe determining behavior organization.

Conventional cytogenetic characterization of a new cell line, ACP01, established from a primary human gastric tumor

Gastric cancer is the second most frequent type of neoplasia and also the second most important cause of death in the world. Virtually all the established cell lines of gastric neoplasia were developed in Asian countries, and western countries have contributed very little to this area. In the present study we describe the establishment of the cell line ACP01 and characterize it cytogenetically by means of in vitro immortalization. Cells were transformed from an intestinal-type gastric adenocarcinoma (T4N2M0) originating from a 48-year-old male patient. This is the first gastric adenocarcinoma cell line established in Brazil. The most powerful application of the cell line ACP01 is in the assessment of cytotoxicity. Solid tumor cell lines from different origins have been treated with several conventional and investigational anticancer drugs. The ACP01 cell line is triploid, grows as a single, non-organized layer, similar to fibroblasts, with focus formation, heterogeneous division, and a cell cycle of approximately 40 h. Chromosome 8 trisomy, present in 60 percent of the cells, was the most frequent cytogenetic alteration. These data lead us to propose a multifactorial triggering of gastric cancer which evolves over multiple stages involving progressive genetic changes and clonal expansion.