Purification ofPseudomonas fluorescens subsp.cellulosa endoglucanases produced inEscherichia coli

Both plasmid pPFC4, which contains 10.6 kb, and a derivative of pPFC4—viz., pPFC4-4.6—which contains 4.6 kb ofPseudomonas fluorescens subsp.cellulosa DNA, direct the synthesis of six distinct endoglucanases inEscherichia coli. Two of these enzymes were purified to homogeneity in a single step by means of anion exchange HPLC. One enzyme has a molecular weight of 30.0 ± 1.0 kDa, an isoelectric point of 7.5, and a specific activity of 3470 U of activity/mg of protein, whereas the other has a molecular weight of 38.5 ± 1.0 kDa, an isoelectric point of 6.7, and a specific activity of 18,050 U of activity/mg of protein. On the basis of the amino acid composition, the 38.5 kDa enzyme appears to be a modified version of the 30.0 kDa enzyme. Thus, the multiplicity of endoglucanases produced inE. coli/pPFC4-4.6 cells may be owing to the posttranslational modification of a smaller number of primary translation products.     

Heritable differences in turning behavior of rats

An attempt was made to breed strains of strongly and weakly rotating rats. A strain difference in rotation parameters was limited to females and developed gradually over eight generations before asymptoting. Unexpectedly, a left-sided population bias developed in both male and female rats bred for weak rotation. It is suggested that testosterone modulates several aspects of the inheritance of cerebral lateralization.     

Familial frontotemporal dementia with neuronal intranuclear inclusions is not a polyglutamine expansion disease

Background  

Many cases of frontotemporal dementia (FTD) are familial, often with an autosomal dominant pattern of inheritance. Some are due to a mutation in the tau- encoding gene, on chromosome 17, and show an accumulation of abnormal tau in brain tissue (FTDP-17T). Most of the remaining familial cases do not exhibit tau pathology, but display neuropathology similar to patients with dementia and motor neuron disease, characterized by the presence of ubiquitin-immunoreactive (ub-ir), dystrophic neurites and neuronal cytoplasmic inclusions in the neocortex and hippocampus (FTLD-U). Recently, we described a subset of patients with familial FTD with autopsy-proven FTLD-U pathology and with the additional finding of ub-ir neuronal intranuclear inclusions (NII). NII are a characteristic feature of several other neurodegenerative conditions for which the genetic basis is abnormal expansion of a polyglutamine-encoding trinucleotide repeat region. The genetic basis of familial FTLD-U is currently not known, however the presence of NII suggests that a subset of cases may represent a polyglutamine expansion disease.