Risk assessment of the presence of polycyclic aromatic hydrocarbons (PAHs) in coastal areas of Thailand affected by the 2004 tsunami.

The total concentrations of twelve, likely carcinogenic, polycyclic aromatic hydrocarbons (PAHs) (i.e., phenanthrene (Phe), anthracene (An), fluoranthene (Fluo), pyrene (Pyr), benz[a]anthracene (B[a]A), chrysene (Chry), benzo[b]fluoranthene (B[b]F), benzo[k]fluoranthene (B[k]F), benzo[a]pyrene (B[a]P), indeno[1,2,3-cd]pyrene (Ind), dibenz[a,h]anthracene (D[a,h]A), and benzo[g,h,i]perylene (B[g,h]P) in backwash deposits of the 2004 Khao Lak tsunami were carefully investigated and compared with the concentrations of world marine sediments (WMS). In general, ∑12PAHs in this study (i.e., 69.43 ± 70.67 ng g(-1)) were considerably lower than those values observed in marine sediments from Boston (54,253 ng g(-1)), coastal sediments from Barcelona Harbour (15,069 ng g(-1)), and riverine sediment from Guangzhou Channel (12,525 ng g(-1)), but were greater than values from coastal sediments in Rosas Bay (12 ng g(-1)), Santa Ponsa Bay (26 ng g(-1)) and Le Planier (34 ng g(-1)). The total toxic benzo[a]pyrene equivalent (TEQ(Carc)) values calculated for Khao Lak coastal sediments (KCS), Khao Lak terrestrial soils (KTS), and Songkhla Lake sediments (SLS) were 10.3 ± 12.2 ng g(-1), 16.0 ± 47.7 ng g(-1), and 5.67 ± 5.39 ng g(-1), respectively. Concentrations of PAHs at all study sites resulted in risk levels that fell into the "acceptable" range of the US EPA model and were much lower than those of other WMS. The cancer risk levels of PAH content in KCS ranged from 7.44 × 10(-8) to 2.90 × 10(-7), with an average of 1.64 × 10(-7) ± 8.01 × 10(-8); this value is 119 times lower than that of WMS. In addition, soil cleanup target levels (SCTLs) for both non-carcinogens (i.e., Phe, An, Fluo and Pyr) and carcinogens (i.e., B[a]A, Chry, B[b]F, B[k]F, B[a]P, Ind, D[a,h]A and B[g,h,i]P) in the KTS samples were estimated for all target groups, with an average value of 115,902 ± 197,229 ng g(-1).

Control of Clostridium perfringens-induced necrotic enteritis in broilers by target-released butyric acid, fatty acids and essential oils.

The efficacy of target-released butyric acid, medium-chain fatty acids (C(6) to C(12) but mainly lauric acid) and essential oils (thymol, cinnamaldehyde, essential oil of eucalyptus) micro-encapsulated in a poly-sugar matrix to control necrotic enteritis was investigated. The minimal inhibitory concentrations of the different additives were determined in vitro, showing that lauric acid, thymol, and cinnamaldehyde are very effective in inhibiting the growth of Clostridium perfringens. The in vivo effects were studied in two trials in an experimental necrotic enteritis model in broiler chickens. In the first trial, four groups of chickens were fed a diet supplemented with butyric acid, with essential oils, with butyric acid in combination with medium-chain fatty acids, or with butyric acid in combination with medium-chain fatty acids and essential oils. In all groups except for the group receiving only butyric acid, a significant decrease in the number of birds with necrotic lesions was found compared with the infected, untreated control group. In the second trial the same products were tested but at a higher concentration. An additional group was fed a diet supplemented with only medium-chain fatty acids. In all groups except for that receiving butyric acid in combination with medium-chain fatty acids and essential oils, a significant decrease in the number of birds with necrotic lesions was found compared with the infected, untreated control group. These results suggest that butyric acid, medium-chain fatty acids and/or essential oils may contribute to the prevention of necrotic enteritis in broilers.

Effect of organic acids in drinking water during the last 2 weeks prior to slaughter on Salmonella shedding by slaughter pigs and contamination of carcasses.

In this study, we investigated the effect of adding organic acids to the drinking water of finishing pigs 2 weeks prior to slaughter on the shedding and prevalence rate of Salmonella at slaughter. Approximately 600 animals from four Belgian pig herds infected with Salmonella were included. At two herds, the study was conducted twice. Before the start of the study, overshoes were taken at the different herds. Two weeks prior to the expected slaughter date, the pigs were randomly divided into two groups (treatment and control group) each containing on average 50 animals within each herd. The treatment group received from this day onwards acidified drinking water (pH = 3.6-4.0), the control group received non-treated water (pH = 7.8-8.5). All other housing, feeding and management factors were identical in both groups. At the slaughterhouse, 10 pigs of each group (20 pigs for each group of study group 6) were randomly selected and sampled (blood, contents of ileum and rectum, mesenteric lymph nodes and carcass swabs). All samples were immediately transported to the laboratory and submitted to Salmonella isolation. Salmonella was isolated out of 11.9% (66/554) of the samples taken at the slaughterhouse, with the highest frequency found in the content of the ileum (18.7%), followed by 17.8% in the lymph nodes, 7.2% in the content of the rectum and 3.6% in the carcass swabs. The results did not reveal a significant difference between the treatment and control groups for the different slaughterhouse samples. The study documented that the investigated control strategy namely, the strategic application of organic acids during the last 2 weeks prior to slaughter was insufficient to decrease Salmonella shedding and contamination shortly before and during slaughter.

The Helmholtz Network for Bioinformatics: an integrative web portal for bioinformatics resources.

SUMMARY: The Helmholtz Network for Bioinformatics (HNB) is a joint venture of eleven German bioinformatics research groups that offers convenient access to numerous bioinformatics resources through a single web portal. The 'Guided Solution Finder' which is available through the HNB portal helps users to locate the appropriate resources to answer their queries by employing a detailed, tree-like questionnaire. Furthermore, automated complex tool cascades ('tasks'), involving resources located on different servers, have been implemented, allowing users to perform comprehensive data analyses without the requirement of further manual intervention for data transfer and re-formatting. Currently, automated cascades for the analysis of regulatory DNA segments as well as for the prediction of protein functional properties are provided. AVAILABILITY: The HNB portal is available at http://www.hnbioinfo.de

Synthesis of 3'-thioamido-modified 3'-deoxythymidine-5'-triphosphates and their use as chain terminators in Sanger-DNA sequencing.

The thioamide derivatives 3'-deoxy-5'-O-(4,4'-dimethoxytrityl)-3'-[(2-methyl-1-thioxo- propyl)amino]thymidine 1 and 3'-deoxy-5'-O-(4,4'-dimethoxytrityl)-3'-((6-([(9H-(fluo-ren-9- ylmethoxy)carbonyl]-amino)-1-thioxohexyl)amino) thymidine 2 were synthesized by regioselective thionation of their corresponding amides 7 and 8 with 2,4-bis(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane-2,4-disulfide (Lawesson's reagent). The thioamides were converted into the corresponding 5'-triphosphates 3 and 4. Compound 3 was chosen for DNA sequencing experiments and 4 was further labelled with fluorescein.

Leptin responsiveness and gene dosage for leptin receptor mutation (fa) in newborn rats.

To determine the degree to which the leptin receptor mutation (fa) influences the responsiveness to leptin during the first postnatal week, we injected recombinant leptin (600 pmol. g-1. day-1 sc from day 1 to day 7) into wild-type (+/+), heterozygous (+/fa), and fatty (fa/fa) rat pups. Growth and final body fat content of these leptin-treated pups were compared with those of saline-treated littermates of the same genotype. The body mass of the leptin-treated +/+ pups, but not that of the +/fa and fa/fa pups, increased more slowly than that of their respective controls, and fat content at day 7 was reduced by 37% in +/+ pups, by 22% in +/fa pups, but not at all in fa/fa pups. Plasma leptin remained excessively high throughout the day under this treatment, but a 30-fold lower leptin dose, causing only moderate changes of plasma leptin, still reduced the body fat of +/+ pups significantly. We conclude that leptin participates in the control of even the earliest stages of fat deposition and that the response to supraphysiological doses of leptin is markedly reduced in 1-wk-old pups with one fa allele and absent in pups with two fa alleles.

Leptin selectively increases energy expenditure of food-restricted lean mice.

OBJECTIVE: To find out whether leptin can attenuate hypometabolic torpor-like states of metabolic rate (MR) in adult lean animals, as it attenuates the morning suppression of thermoregulatory thermogenesis in suckling-age rat pups. DESIGN: Leptin effects on MR and food intake were studied in mice aged 4-7 months, in which a high incidence of exaggerated circadian reductions of MR had been induced by chronic food-restriction and, for comparison, in free-feeding mice. PROTOCOL: Continuous recordings of MR, for a group of seven mice maintained at an ambient temperature of 24 degrees C, while they were repeatedly-with pauses of at least six days-treated for three consecutive days with either recombinant murine leptin (20, 200 or 600 pmol x g(-1) x d[-1]) or saline. RESULTS: Leptin treatment caused dose-dependent 5-15% increases in energy expenditure by moderating the decreases in MR during the circadian minima, without affecting either the MR during the circadian maxima or food intake. Similar treatment of free-feeding mice caused dose-dependent decreases of food intake without changing MR. CONCLUSION: Leptin controls thermoregulatory energy expenditure when food supplies are scarce and changes food intake, rather than energy expenditure, when food is abundant.

The leptin receptor mediates apparent autocrine regulation of leptin gene expression.

The possibility that the leptin receptor (LEPR) mediates autocrine regulation of leptin expression in adipose tissue was examined in 10-day-old Zucker rat pups with different copy numbers of the leptin receptor mutation (Lepr(fa)). Plasma leptin concentrations and adipose tissue mRNA levels for leptin were related to copy number of the mutation (fa/fa > fa/+ > +/+). These relationships were independent of plasma insulin concentration. Reduced copy number for the functional leptin receptor apparently results in a diminished negative feedback signal to the leptin gene in adipose tissue. Thus, leptin appears to close a short regulatory loop controlling its own synthesis in adipose tissue.

Different physiological traits underlying increased body fat of fatty (fa/fa) and heterozygous (+/fa) rats.

To find out whether the most characteristic physiological traits distinguishing suckling-age fa/fa pups from lean littermates also differ between +/+ and +/fa littermates, we analyzed the body composition and cold defense of 7- and 16-day-old pups and the plasma concentrations of insulin, glucose, triglycerides, and free fatty acids in 16-day-old pups. Zucker rat x Brown Norway hybrid pups were genotyped by using a molecular marker within 0.5 cM of the fa gene. At both ages the +/fa pups had significantly more body fat than their +/+ littermates. At 7 days this difference was as large as that between +/fa and fa/fa pups, but at 16 days it was only one-seventh of the fa/fa vs. +/fa difference. In contrast, there were no heterozygote differences for three parameters that show crucial abnormalities in the fa/fa pups: thermoregulatory thermogenesis and plasma concentrations of insulin and triglycerides. The physiological mechanisms underlying the increased fat content of +/fa pups thus differ from those known to fuel most of the excessive fat deposition of their fa/fa littermates.