Purification of human cartilaginous proteoglycans and technical aspects of the radioimmunoassay

Proteoglycans (PG) have been purified by classical methods from human articular cartilage in order to set up a radioimmunoassay. Conditions of labelling, purification of labelled PG, and optimal conditions of buffer, temperature, duration of incubations and dilution of antiserum are described. Separation of free and bound PG is performed by immunoprecipitation. It is demonstrated that human articular PG can be assayed quantitatively by RIA procedure, with the sensitivity of +/- 2 femto-moles (+/- 5 ng) per tube.     

CHOLINE ACETYLTRANSFERASE, ACETYLCHOLINESTERASE AND AROMATIC l-AMINO ACID DECARBOXYLASE IN SINGLE IDENTIFIED NERVE CELL BODIES FROM SNAIL HELIX ASPERSA

—The distribution of choline acetyltransferase, aromatic l -amino acid decarboxylase and acetylcholinesterase in the nervous system of Helix aspersa has been studied using homogenates of whole ganglia, microdissection from freeze-dried sections and dissection of single neurons from fresh tissue. Choline acetyltransferase was found in both the cell body and neuropil layers of all the Helix ganglia. The enzyme was not specifically localized to any ganglion or region of ganglion. Between 10 and 30 per cent of the isolated single cell bodies contained the enzyme. The enzymic activity corresponded to 50–200 mmol ACh/1 cell bodies/h. Choline acetyltransferase is probably a specific marker for cholinergic cells in this species. Aromatic l -amino acid decarboxylase was more selectivity localized and its distribution corresponded well with that of monoamine containing cells as visualized by the fluorescence histochemical technique. A large proportion of cell bodies were localized in the boundary between the visceral and right parietal ganglia and in the pedal ganglion. The other ganglia contained few such cells. The activity of aromatic l -amino acid decarboxylase corresponded 10–50 mmol dopamine/1 cell bodies/h. A method was developed to measure the enzyme activity towards 5-hydroxytryptophan and DOPA in single cells simultaneously. The ratio between the activity towards both substrates did not vary significantly for the different cells. The enzyme is probably a specific marker for monoamine cells, but cannot be used to differentiate between the different monoamine cells. Acetylcholinesterase was uniformly distributed in the ganglia and was probably present in all nerve cells.     

Ontogeny of the proventitious epicormic buds in Quercus petraea.

In the present work, we described the fate of proventitious epicormic buds on the trunks of 40-year-old Quercus petraea trees and in parallel the vascular trace they produced in the wood. Our results show that small and large individual epicormic buds can survive as buds for 40 years and that both are composed of a terminal meristem and scales. Meristematic areas are detected in the scale axils of small buds; in addition to these meristems the large buds also have secondary bud primordia. The small buds are connected to the pith of the main stem by a unique trace, whereas the large buds are connected by one or multiple traces. A single trace might imply that the whole bud is still alive and multiple traces might indicate that the terminal meristem has died. In the latter case, each trace is connected to a secondary bud of the large bud. The buds found in a cluster are composed of a terminal meristem and scales with axillary meristems in the scale axils. A cluster is connected to the pith of a stem either by a unique trace when it seems to be the result of partial abscission of an epicormic shoot or multiple traces when it might have originated from an epicormic bud in which the terminal meristem has died. Whatever the type of the bud, the vascular trace in the bark is composed of a cambium, secondary xylem and parenchyma cells and the trace present in the wood had parenchyma cells with vestiges of secondary xylem. Each year, the vascular trace should be produced in the bark by the cambium of the tree but not by the bud itself. On 40-year-old Q. petraea, we observed a proliferation of epicormic buds and in parallel a multiplication of the number of vascular traces in the trunk, but the knots caused by the traces of epicormic buds in the wood, either as individuals or in clusters, are minor since their colours are only slightly darker than those of woody rays and they are less than 2 mm in diameter. The knots will appear when epicormic buds develop into shoots. Received: 30 March 1999 / Accepted: 09 June 1999