Production of Biomass-Based Automotive Lubricants by Reductive Etherification.

Growing concern with the effects of CO2 emissions due to the combustion of petroleum-based transportation fuels has motivated the search for means to increase engine efficiency. The discovery of ethers with low viscosity presents an important opportunity to improve engine efficiency and fuel economy. We show here a strategy for the catalytic synthesis of such ethers by reductive etherification/O-alkylation of alcohols using building blocks that can be sourced from biomass. We find that long-chain branched ethers have several properties that make them superior lubricants to the mineral oil and synthetic base oils used today. These ethers provide a class of potentially renewable alternatives to conventional lubricants produced from petroleum and may contribute to the reduction of greenhouse gases associated with vehicle emissions.

Temporal changes in gene expression in the liver of male plaice (Pleuronectes platessa) in response to exposure to ethynyl oestradiol analysed by macroarray and Real-Time PCR.

Suppression subtractive hybridisation (SSH) was used to generate cDNA libraries representing genes differentially-expressed in liver from male plaice (Pleuronectes platessa) exposed to ethynyl oestradiol (EE2). BLAST analysis and alignments of the clones with database sequence suggested at least three vitellogenin (VTG) genes and three zona radiata protein (ZRP) genes were represented. Clones with unique sequence (62 up-, 13 down-regulated) were arrayed as probes on nylon membranes to investigate temporal expression of oestrogen-responsive genes in experimental animals. Arrays were hybridised with radiolabelled cDNAs prepared from hepatic mRNA from animals treated with EE2 for various times upto 21 days and from treated animals transferred to clean water for upto a further 31 days. By day 21 of treatment 11 out of 17 probes from unidentified genes, 21/22 VTG, 13/14 ZRP, 2/2 liver aspartic proteinase (LAP) and 8/10 other gene sequences were induced by EE2 exposure. Of the down-regulated sequences, only three showed significant, decreased expression and these encode cytochrome b and two with cryptic functions. Based on the pattern of temporal response the up-regulated probes fell into two classes. Pattern A reached maximum expression by day 16 of exposure and then declined prior to removal of EE2 at 21 days. Pattern B genes reached maximal expression between day 16 and 22, declining only after removal of EE2. Independent investigation of the expression patterns of selected probes using quantitative Real-Time PCR reproduced the distinctive patterns. The results indicate a previously unrecognised mechanism for oestrogenic toxicity in which there is a selective down-regulation of some egg proteins, potentially diminishing the quality of eggs and this may contribute to reproductive failure described elsewhere.

Identification of transcriptional effects of ethynyl oestradiol in male plaice (Pleuronectes platessa) by suppression subtractive hybridisation and a nylon macroarray.

Suppression subtractive hybridisation (SSH) was used to generate cDNA libraries representing genes differentially expressed in response to ethynyl oestradiol (EE2) exposure in liver from male plaice (Pleuronectes platessa) previously analysed for vitellogenin (VTG) induction. Characterisation of the cDNA clones identified many as VTG (2 genes) and zona radiata proteins (ZRP) (3 genes), but 40 encoded other proteins, with more than half cryptic. Further analysis identified 85 non-redundant clones suitable for array on nylon membrane. Radiolabelled cDNAs were prepared from hepatic mRNA from EE2 treated plaice (0 and 21 days) and hybridised with the arrayed clones. Analysis of the data showed that 11/17 novel, 21/22 VTG, 13/14 ZRP, 2/2 liver aspartic proteinase (LAP) and 8/10 other mRNAs were up-regulated by EE2 exposure.

Characterisation of choline esterases and their tissue and subcellular distribution in mussel (Mytilus edulis).

Acetylcholinesterase in mussel is potentially a useful biomarker of exposure to organophosphates (OP) in the marine environment. This study looked at cholinesterase activity in subcellular fractions of various tissues from the common mussel, Mytilus edulis. Measurement of enzyme rates demonstrated that although highest specific activity was found in foot 'mitochondrial' fraction, recovery of activity was very low. Gill 'microsomal' fraction had the second highest specific activity with a useful level of recovery and therefore was the most suitable tissue fraction for biomarker applications. Comparative studies of alternative alkylthiocholine substrates and competitive inhibitors suggest there is a single cholinesterase enzyme type present in this fraction. Inhibition of alkylcholine hydrolysis by BW284C51, specific to acetylcholinesterase in vertebrates, showed that cholinesterase activity in gill 'microsomal' fraction is inhibited by this compound but to a lesser extent than in vertebrate AChE. Inhibition of cholinesterase activity by azamethiphos in gill 'microsomal' fraction gave an IC50 of approximately 100 microM and showed both time and concentration dependence. However this indicates a lower potency compared to other animals and it is debatable whether mussel cholinesterase activity is useful as a biomarker of exposure in the field.