Formation of proinsulin by immobilized Bacillus subtilis

There has been an increasing interest in the use of immobilized cells for the production of pharmaceuticals as well as for products such as high fructose syrup or ethanol. Some of these compounds are now produced on an industrial scale whereby the cells are used in a resting or growing state or in a nonviable form as natural carriers of the enzyme(s) involved in the synthesis. The advantages of immobilized cell technology should also apply to microorganisms modified by recombinant DNA techniques to produce a variety of eukaryotic proteins such as hormones. We describe here the properties of immobilized Bacillus subtilis cells carrying plasmids encoding rat proinsulin. Cell proliferation normally coupled to DNA replication is undesirable in immobilized cell systems as "clogging' of the system occurs due to cells growing outside the beads. Therefore, different ways were investigated to inhibit cell division while allowing continued protein synthesis. We found that the addition of certain antibiotics in the growth medium, such as novobiocin which inhibits DNA replication, fulfills these requirements, allowing proinsulin synthesis and excretion to take place over a period of several days.     

Tissue ascorbic acid and a liver dehydroascorbatase in guinea-pigs.

The extraction, partial purification and assay of a dehydroascorbatase from guinea-pig liver is described. There was no evidence that changes in dehydroascorbatase activity could account for the modified tissue ascorbic acid concentrations associated with aging or with the ingestion of fluoride, flavonoids or anthocyanin material.     

Carbamazepine inhibits NMDA-induced depolarizations in cortical wedges prepared from DBA/2 mice

There is some doubt as to the mechanism of action of the widely-used anticonvulsant drug, carbamazepine. In cortical wedges prepared from genetically epilepsy-prone DBA/2 mice, carbamazepine at therapeutic concentrations (1–10 M) markedly reduced the depolarization produced by N-methyl-D-aspartate (NMDA). The NMDA sub-type of glutamate receptor has been implicated in the pathogenesis of epilepsy and the inhibitory action of carbamazepine on this response suggests that the anticonvulsant action of the drug may be due to its blockade of NMDA receptor-mediated events.     

Critique of Manualized Therapies: Systemic Family Therapy Manual for Adolescent Self-Harm

Systemic Practice and Action Research - The ‘Systemic Family Therapy Manual for Adolescent Self-Harm’ (SHIFT) (Boston et al. 2009) has recently been evaluated and it was found that the...