The effect of nerve lesions upon the dendritic branching of the metathoracic 'fast' coxal depressor motoneurone in the adult cockroach, Periplaneta americana has been studied by intracellular cobalt injection. Dendrites may sprout after several nerve trunks entering the metathoracic ganglion are lesioned. Direct surgical damage to the neurone is not a pre-requisite for sprouting. New sprouts ma...

1. Methods for presenting dose-response data for the ganglionic actions of cholinergic agonists (e.g. carbamylcholine) are compared, using the mannitol-gap technique for electrophysiological recording of synaptic events at the cercal nerve, giant fibre synapse of the sixth abdominal ganglion of the cockroach Periplaneta americana. 2. At concentrations around 10(-5)M, carbamylcholine has no effe...

Production of methane in the hindgut of the cockroach Periplaneta americana was found to vary, depending on the feeding regimen. Methane production was positively correlated with the numbers of the ciliate Nyctotherus ovalis living in the cockroach hindgut. Defaunation of the cockroaches by means of low concentrations of metronidazole (Flagyl) resulted in a quick drop of methane production. Add...

Three thousand Periplaneta americana were sacrificed and the following data collected: number parasitized by oxyurid nematodes, age, sex, weight, length, specific gravity of hemolymph, differential cell counts of hemocytes, and the number of each nematode species present. The mean number of nematodes per host for adults and nymphs, and males and females were compared using the Student's Mest. T...

Random amplified DNA markers (RAPD; Williams et al., 1990) were used to obtained specific RAPD fragments characterising different species of oxyuroids. We tested six species of worms parasitizing vertebrates or invertebrates: Passalurus ambiguus Rudolphi, 1819, parasite of Leporids; Syphacia obvelata (Rudolphi, 1802) Seurat, 1916, a parasite of rodents; Blatticola blattae (Graeffe, 1860) Chitwo...

Cobalt backfills from the thoracic connectives of the hatchling Periplaneta americana allowed identification of giant interneurones in the terminal abdominal ganglion, morphologically comparable to GI 1, 2 and 3 in the adult. The bipolar neurone innervating each cercal filiform wind receptor hair is ultrastructurally similar to the adult cell and possesses an individually identifiable afferent ...