Unintended changes in cognition, mood, and behavior arising from cell-based interventions for neurological conditions: ethical challenges.

The prospect of using cell-based interventions (CBIs) to treat neurological conditions raises several important ethical and policy questions. In this target article, we focus on issues related to the unique constellation of traits that characterize CBIs targeted at the central nervous system. In particular, there is at least a theoretical prospect that these cells will alter the recipients' cognition, mood, and behavior-brain functions that are central to our concept of the self. The potential for such changes, although perhaps remote, is cause for concern and careful ethical analysis. Both to enable better informed consent in the future and as an end in itself, we argue that early human trials of CBIs for neurological conditions must monitor subjects for changes in cognition, mood, and behavior; further, we recommend concrete steps for that monitoring. Such steps will help better characterize the potential risks and benefits of CBIs as they are tested and potentially used for treatment.

Survival of free DNA encoding antibiotic resistance from transgenic maize and the transformation activity of DNA in ovine saliva, ovine rumen fluid and silage effluent.

To assess the likelihood that the bla gene present in a transgenic maize line may transfer from plant material to the microflora associated with animal feeds, we have examined the survival of free DNA in maize silage effluent, ovine rumen fluid and ovine saliva. Plasmid DNA that had previously been exposed to freshly sampled ovine saliva was capable of transforming competent Escherichia coli cells to ampicillin resistance even after 24 h, implying that DNA released from the diet could provide a source of transforming DNA in the oral cavity of sheep. Although target DNA sequences could be amplified by polymerase chain reaction from plasmid DNA after a 30-min incubation in silage effluent and rumen contents, only short term biological activity, lasting less than 1 min, was observed in these environments, as shown by transformation to antibiotic resistance. These experiments were performed under in vitro conditions; therefore further studies are needed to elucidate the biological significance of free DNA in the rumen and oral cavities of sheep and in silage effluent.

Characterisation of a Rrhodobacter sphaeroides gene that encodes a product resembling Eescherichia coli cytochrome b(561) and R. sphaeroides cytochrome b(562).

Analysis of the photoactive yellow protein (pyp) gene region of Rhodobacter sphaeroides has revealed the presence of an additional open reading frame, orfD, that had not previously been identified. Here we report the location of this new gene and the predicted amino acid sequence of the encoded protein. The translation product resembles a group of small cytochrome b-like proteins, including Escherichia coli cytochrome b(561), R. sphaeroides cytochrome b(562), and two new cytochrome b(561)-like proteins identified using the E. coli genome sequence, for which functions have not yet been established. To determine OrfD function in R. sphaeroides, an orfD mutant was constructed. The OrfD mutant exhibited growth rates and yields very similar to those of the wild-type strain when grown under a variety of growth conditions. Respiration rates, reduced-minus-oxidised spectra and levels of photosynthetic complexes were also very similar in the two strains. Although the role of OrfD was therefore not determined here, we demonstrate that the orfD gene is expressed in R. sphaeroides under aerobic, semi-aerobic and photosynthetic growth conditions.