The calf muscles of the rat hindlimb are composed of smaller entities, called neuromuscular compartments, which are the territories of muscle innervated by a single, naturally occurring primary (first-order) muscle nerve branch. While it is quite clear that a precise connectivity exists very early in development between motoneuron pools and individual muscles, the mechanisms responsible for producing the adult pattern of compartmental innervation are unknown. This study uses intracellular recording techniques to demonstrate that neuromuscular compartments are essentially established at birth and that postnatal synapse elimination has little role in establishing neuromuscular compartments. Our results demonstrate the existence of a small number of cross-compartmental connections in neonates which are not present in adults. Examining the removal of these cross-compartmental connections in both normal muscles and in muscles that have had synapse elimination delayed by tenotomy reveals that the synapses responsible for this innervation are eliminated in a selective manner.
Protostrongylid larvae were recovered from the faeces or lungs of red deer (Cervus elaphus), roe deer (Capreolus capreolus) and reindeer (Rangifer tarandus) in Scotland during 1981. Typical protostrongylid first-stage larvae were also recovered from possible intermediate hosts, the grey field slug (Agriolimax reticulata) and the white-soled slug (Arion fasciatus). All these protostrongylid larvae were microscopically identical to those of the nematode Elaphostrongylus cervi. Despite careful search, adult E cervi were not found, but it is concluded that infection with E cervi is widespread in Scottish deer.
The serological findings demonstrate that these animals are constantly exposed to infection with Leptospira in their environment, but it is not known if platypuses suffer from clinical leptospirosis or if they mount an immune response, but are unaffected by the bacteria. The prevalence of Leptospira infection among the platypus population could not be precisely estimated because of the unknown number of individuals inhabiting the Wollondilly River inside the survey property. Domestic livestock, mostly cattle, may be the major source of Leptospira infection. The effects of this disease on population dynamics and on reproduction in wild platypuses are not well understood. The role of other wildlife in the transmission and maintenance of Leptospira in the environment is unknown.
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