Evaluation of the phagocytosis of microspheres in V79 cells by flow cytometry

Phagocytosis of microspheres in V79 Chinese hamster lung cells was investigated by flow cytometry. Fluorescent microspheres (1.8 micron diameter) were used as the ingesta. Change in the number of V79 cells containing fluorescent microspheres was measured as an index of phagocytic activity. With time there was a sigmoidal increase in cells containing microspheres. The phagocytosis of microspheres is partially explained by two parameters introduced to describe the sigmoidal curves.     

The role a botanical institute can play in the conservation of the terrestrial biodiversity in a developing country

The need to integratein situ conservation into the planning process is outlined, and the importance of vegetation survey to determine conservation priorities and to identify areas suitable forin situ conservation is stressed. A case is presented, drawing on experience gained in Zimbabwe, of how a botanical institute can become an integral part of biological conservation. The institute should consist of a herbarium, a botanical garden, a gene bank and a vegetation survey unit. The function of each section, how they interlink, and how they can be integrated are discussed.     

The role of introns in evolution

What are the roles of 'classical' introns in the evolution of nuclear genes, and what was the origin of these introns? Exon shuffling has been important in the evolution of cell surface and extracellular proteins, but the evidence for it in respect of intracellular proteins is weak. Intron distributions imply that some introns have been removed while others have been inserted in the course of evolution: ancestral patterns of introns may thus have been obscured. Recent evidence on the self-splicing and reverse-splicing abilities of Group II introns supports the hypothesis that these could have been the ancestors of classical introns.