Metabolic activation of pyrrolizidine alkaloids by human, rat and avocado microsomes.

Two pyrrolizidine alkaloids and one pyrrolizidine alkaloid-N-oxide were incubated with microsomal preparations from humans, rat and avocado and the product profiles examined. The alkaloids were converted to dehydroretronecine, the putative toxic metabolite, by both rat and human microsomal preparations. In addition, alkaloid-N-oxides, the major detoxication products from pyrrolizidine alkaloids, were also formed.

Nuclear DNA content of human breast carcinoma: a comparison of results obtained by microspectrophotometry and flow cytometry of paraffin embedded tissue.

This study compares 2 techniques for estimating the nuclear DNA content of tumor cell lines: (i) static cytometry of smears taken from fresh tissue and (ii) flow cytometry of cells extracted from paraffin embedded tissue. Parallel determinations of DNA content, using both techniques, were made on samples of tissue taken from 130 female patients with breast carcinoma. Using a simple classification into diploid and non-diploid groups, the 2 techniques yielded discrepant results in 11% of cases.

Genomic subtractive hybridization to isolate species-specific DNA sequences in insects.

Selective enrichment has been used in a number of instances for the isolation of species-specific sequences in prokaryotes. This paper reports the successful application of the technique to insects. Genomic probes were derived to the target species D.

Chloroplast gene expression in lettuce grown under different irradiances.

Chloroplast DNA sequences have been used as hybridisation probes to measure the levels of RNA transcripts present in low- and high-light-grown lettuce (Lactuca sativa L.) plants. The transcript levels for rbc L, psa A, psb A and rDNA are not different between these two light regimes.