Characteristics of five cell types appearing during in vitro culture of embryonic material from Drosophila melanogaster

Abstract

Although attempts have been made over a number of decades to achieve successful tissue culture of Drosophila material (see Schneider, 1964), progress has been held back until recently by a lack of basic information on the chemical and physiological characteristics of the haemolymph of the organism necessary for a reasoned formulation of a culture medium. In 1963, Begg & Cruickshank published details of the mineral composition, osmotic pressure and pH of the haemolymph of third instar larvae, and this has provided the basis for a more satisfactory approach, as reflected in an increasing amount of fruitful work since reported. Much of this work has been done with embryonic material. Horikawa & Fox (1964) claimed continuous multiplication of a small type of early embryonic cell; Lesseps (1965) described re-aggregation of dissociated embryonic cells in culture, with possible development of muscle cells, nerve cells and oenocytes in the aggregates; in the same year, Echalier, Ohanessian & Brun (1965) noted the emergence of free contractile elements and a polygonal type of cell in embryonic cultures, with the later development of a fibroblastic type of cell; Gvozdev & Kakpakov (1968) reported the appearance of a small type of cell growing in multilayer clumps as well as of fibroblast-and epithelial-type cells, and Seecof & Unanue (1968) reported the development of free neuron-like cells and muscle cells. Results are presented below of a further investigation into the behaviour of Drosophila melanogaster embryonic cells in culture, and the characteristics of five distinct cell types are described. These comprehend the types mentioned above (and to some extent there is necessarily repetition of the earlier work) but, as well as bringing the previously isolated observations into a single study, greater detail is given of the form and mode of development of the elements, and some account of the dynamic activities of some of them is included.