Cockroach Hindgut Research Articles

Cultivationin vitroofEndolimax blattaeLucas, 1927 from the cockroach hind gut

Endolimax blattae, a small amoeba living in the cockroach hind gut, was cultivatedin vitrofor the first time.Growth and encystment took place in diphasic serum-saline media with or without the addition of starch.E. blattaegrew well at 25 and 37°C. At the latter temperature the flagellates andBlastocystiswhich contaminated recently isolated strains were eliminated.More amoebae and cysts were produced in cultures supplied with starch than in those without starch, and there seemed to be a relationship between depletion of starch and onset of encystment.The results are discussed with reference to conditions in the natural environment.I wish to express my thanks to Professor H. P. Moon, in whose department this work was carried out, for his help and advice, to my supervisor Dr Marjorie G. Guthrie for her advice, encouragement and constructive criticism, and to Dr Ann Bishop, F.R.S., and Dr Elspeth W. McConnachie for their invaluable advice onin vitrocultivation.

Pharmacological Studies on the Isolated Hindgut Movement of American Cockroach, Periplaneta americana L. (Blattaria : Blattidae) : I Effects of Cholinesters, Bioactive Amines, Amino Acids and Several Autonomic Nerve Agents

This experiment was undertaken to see effects of cholinesters, some bioactive amines, amino acids, several autonomic nerve agents and some miscellaneous compounds on the isolated cockroach hindgut movement. Cholinesters produced rather mild effect than other agents, they tend to increase the coordination, frequency and amplitude of the hindgut movement, but did not induce the contraction of hindgut. Acetylcholine had high effectiveness and its threshold of effective concentration was 10-8 g/ml. Tryptamine analogues produced increases of contraction, amplitude and frequency. Contraction of hindgut was a specific action by these agents, and this contraction seemed to be good for hindgut movement. Serotonin had the highest effectiveness among all tested compounds, its threshold of effective concentration was 10-11 g/ml. Catechol and phenyl amines showed very high increases of amplitude and frequency in a short while after application, however these stimulatory actions were followed by progressive decreases of amplitude and frequency. Glutamic acid and glutamine had high stimulatory action among amino acids, their threshold of effective concentrations were about 10-8 g/ml, many other amino acids had little or no effect on the hindgut movement. The present studies involved discussion of possible receptor system.