The effect of aluminium in Atlantic salmon (Salmo salar) with special emphasis on alkaline water

Atlantic salmon (Salmo salar) parr were exposed to aluminium under both steady state and non-steady state chemical conditions in alkaline water. Under alkaline (pH 9.5) steady state conditions, approximately 350 microg Al l(-1) (predominantly aluminate, Al(OH)(4)(-)) had no acute toxic effect on the salmon. The fish, however, showed a physiological response after 3 weeks of exposure ( approximately 300% increase in blood glucose concentration, about 30% increase in blood haematocrit, and about 15% decrease in plasma Cl(-) concentration). No increase in toxicity was evident under non-steady state conditions, i.e. lowering Al solubility as pH was lowered from 9.5 to 7.5. The results indicate that the toxicity of the aluminate ion (Al(OH)(4)(-)) is low, and particularly lower than the corresponding toxicity of cationic Al hydroxides. The effects observed in fish exposed to Al-rich water at pH 9.5 were counteracted as Al solubility was decreased by lowering pH to 7.5. This is contrary to previous observations where Al solubility has been lowered by increasing pH from 5.0 to 6.5.     

Artifact production in the assay of anhydroecgonine methyl ester in serum using gas chromatography-mass spectrometry

The detection of the pyrolysis product anhydroecgonine methyl ester (AEME, methylecgonidine) after cocaine smoking using gas chromatography-mass spectrometry is hampered by the artifactual production of AEME. The amount of AEME increases with the amount of cocaine used producing false positive values in authentic samples. A method for the correction of quantitative values was established using calibration of pyrolysis and estimation of the artifactual AEME. Authentic AEME in serum was differentiated from the artifact above 3.5 microg/l, 99% prediction limits of the quantitation were +/-3.1 microg/l. In 16 serum samples and five postmortem blood samples, cocaine and AEME were detected, but after application of the correction method only ten were truly positive for AEME.     

Effects of crude extracts of Agaricus blazei on DNA damage and on rat liver carcinogenesis induced by diethylnitrosamine

The effects of crude extracts of the mushroom Agaricus blazei Murrill (Agaricaceae) on both DNA damage and placental form glutathione S-transferase (GST-P)-positive liver foci induced by diethylnitrosamine (DEN) were investigated. Six groups of adult male Wistar rats were used. For two weeks, animals of groups 3 to 6 were treated with three aqueous solutions of A. blazei (mean dry weight of solids being 1.2, 5.6, 11.5 and 11.5 mg/ml, respectively). After this period, groups 2 to 5 were given a single ip injection 200 mg/kg DEN and groups 1 and 6 were treated with 0.9% NaCl. All animals were subjected to 70% partial hepatectomy at week five and sacrificed 4, 24 and 48 h or 8 weeks after DEN or 0.9% NaCl treatments (10th week after the beginning of the experiment). The alkaline comet assay and GST-P-positive liver foci development were used to evaluate the influence of the mushroom extracts on liver cell DNA damage and on the initiation of liver carcinogenesis, respectively. Previous treatment with the highest concentration of A. blazei (11.5 mg/ml) significantly reduced DNA damage, indicating a protective effect against DEN-induced liver cytotoxicity/genotoxicity. However, the same dose of mushroom extract significantly increased the number of GST-P-positive liver foci.     

Engineering increased vitamin C levels in plants by overexpression of a D-galacturonic acid reductase

L-Ascorbic acid (vitamin C) in fruits and vegetables is an essential component of human nutrition. Surprisingly, only limited information is available about the pathway(s) leading to its biosynthesis in plants. Here, we report the isolation and characterization of GalUR, a gene from strawberry that encodes an NADPH-dependent D-galacturonate reductase. We provide evidence that the biosynthesis of L-ascorbic acid in strawberry fruit occurs through D-galacturonic acid, a principal component of cell wall pectins. Expression of GalUR correlated with changing ascorbic acid content in strawberry fruit during ripening and with variations in ascorbic acid content in fruit of different species of the genus Fragaria. Reduced pectin solubilization in cell walls of transgenic strawberry fruit with decreased expression of an endogenous pectate lyase gene resulted in lower ascorbic acid content. Overexpression of GalUR in Arabidopsis thaliana enhanced vitamin C content two- to threefold, demonstrating the feasibility of engineering increased vitamin C levels in plants using this gene.     

Current approaches to whole genome phylogenetic analysis

It has long been known that evolutionary trees (phylogenies) can be estimated by comparing the DNA or protein sequences of homologous genes across different organisms. More recently, attempts have been made to estimate phylogenies by comparing entire genomes. These attempts have focused largely on comparisons of gene content and gene order. Many different methods have been proposed for making these comparisons. These include primarily maximum parsimony and distance methods, although more recently maximum likelihood and Bayesian methods are being developed. This paper discusses each of these approaches in turn, including their merits and limitations, and any software which is available to make use of them.     

ESF Programme on Functional Genomics 1st European Conference: Functional Genomics and Disease 2003

In this report from the 1st European Conference of the European Science Foundation Programme on Functional Genomics, we provide coverage of the high-profile plenary talks and a cross-section of the many presentations in the disease analysis symposia and functional genomics technologies workshops.     

Meeting highlights: genome informatics

We bring you the highlights of the second Joint Cold Spring Harbor Laboratory and Wellcome Trust 'Genome Informatics' Conference, organized by Ewan Birney, Suzanna Lewis and Lincoln Stein. There were sessions on in silico data discovery, comparative genomics, annotation pipelines, functional genomics and integrative biology. The conference included a keynote address by Sydney Brenner, who was awarded the 2002 Nobel Prize in Physiology or Medicine (jointly with John Sulston and H. Robert Horvitz) a month later.     

Horizontal transmission of epizootic ulcerative syndrome (EUS)-associated virus in the snakehead Ophicephalus striatus under simulated natural conditions

Natural transmission of the epizootic ulcerative syndrome (EUS) was conducted on na?ve snakeheads Ophicephalus striatus (also known as Channa striata) kept (A) in aquifer water, (B) in lakewater, (C) cohabiting with EUS snakeheads in lakewater, and (D) cohabiting with apparently healthy snakeheads in lakewater during the 1994 to 1995 EUS season. The results showed that EUS-like lesions developed in 6 to 14 d among na?ve snakeheads cohabiting with EUS snakeheads and with apparently healthy snakeheads in lakewater (Treatments C and D). Among na?ve fish exposed to lakewater (Treatment B), similar lesions developed in 16 to 21 d, while na?ve fish in aquifer water (Treatment A) did not develop EUS-like lesions. EUS signs began as Grade I (slight) lesions that gradually progressed to Grades III-IV (severe) 3 to 5 d from lesion onset, similar to the naturally affected EUS fish. The virus was recovered from some but not all naturally EUS-affected snakeheads, snakeheads with healing lesions and apparently healthy snakeheads, but not from na?ve snakeheads. The results provide evidence of a waterborne horizontal transmission of the EUS-associated virus. This is the first report of a successful horizontal transmission of the EUS-associated virus from apparently healthy snakeheads to na?ve fish under natural conditions and of virus recovery in tissue culture from naturally exposed experimental fish.     

Taurocholate feeding prevents CCl4-induced damage of large cholangiocytes through PI3-kinase-dependent mechanism

Bile acids are cytoprotective in hepatocytes by activating phosphatidylinositol-3-kinase (PI3-K) and its downstream signal AKT. Our aim was to determine whether feeding taurocholate to CCl(4)-treated rats reduces cholangiocyte apoptosis and whether this cytoprotective effect is dependent on PI3-K. Cholangiocyte proliferation, secretion, and apoptosis were determined in cholangiocytes from bile duct ligation (BDL), CCl(4)-treated BDL rats, and CCl(4)-treated taurocholate-fed rats. In vitro, we tested whether CCl(4) induces apoptosis and whether loss of cholangiocyte proliferation and secretion is dependent on PI3-K. The CCl(4)-induced cholangiocyte apoptosis and loss of cholangiocyte proliferation and secretion were reduced in CCl(4)-treated rats fed taurocholate. CCl(4)-induced cholangiocyte apoptosis, loss of cholangiocytes secretion, and proliferation were prevented by preincubation with taurocholate. Taurocholate cytoprotective effects were ablated by wortmannin. Taurocholate prevented, in vitro, CCl(4)-induced decrease of phosphorylated AKT protein expression in cholangiocytes. The cytoprotective effects of taurocholate on CCl(4) effects on cholangiocyte proliferation and secretion were abolished by wortmannin. Taurocholate protects cholangiocytes from CCl(4)-induced apoptosis by a PI3-K-dependent mechanism. Bile acids are important in the prevention of drug-induced ductopenia in cholangiopathies.