Tris-(2,3-dibromopropyl) isocyanurate (TBC) is a heterocyclic brominated flame retardant that was recently detected in the environment in China.TBC is semi-volatile and can accumulate in the lipid of some species,but little is known about its effect on aquatic organisms.We exposed adult zebrafish to 0,0.25,1 and 4mg/L TBC for 28 d and measured the effect on survival,growth,histopathology,hormone levels,enzyme activity,and gene expression.TBC exposure had no effect on survival or growth.We observed significant damage to the liver and gill,including hepatocellular swelling and fatty degeneration in the liver as well as proliferation and edema of epithelial cells in the gills.In addition,exposure to 4mg/L TBC induced proliferation of goblet cells in the intestine of both sexes,acellular areas in the testis,and thinly scattered vitellogenic granules in vitellogenic oocytes.TBC exposure had no effect on the levels of thyroid hormones,testosterone,estradiol,liver superoxide dismutase activity,malondialdehyde content,and brain cholinesterase activity.By contrast,hepatic vitellogenin and cytochrome P4501A gene expression was significantly down-regulated in both male and female zebrafish in response to TBC exposure.Our results suggest that exposure to TBC causes a variety of potential reproductive and endocrine toxic effects.
Forty-eight vinegar samples including white vinegar, rice vinegar and mature vinegar were collected from several markets in Beijing. Butyltin compounds were determined by headspace solid-phase microextraction coupled with gas chromatography and flame photometric detector after in situ ethylation with sodium tetraethylborate. Butyltin species were detected in sixteen vinegar samples and ranged from 0.012 to 14.10 lag Sn L 1. The detection rate of white vinegar is higher than that of rice vinegar and mature vinegar. Vinegar samples with relatively high butyltin concentration (〉1.5 μg Sn L-1) were those stored in plastic bags, indicating that the plastic bag was one of the possible sources of butyltin contamination. This was further confirmed by the leaching experiments of three selected plastic bags, and monobutyltin was detected in the leaching solvents. According to the estimation, the average daily intake of total butyltin compounds through vinegar consumption is about 0.04 ng Sn/kg b.w., much lower than the Tolerable Daily Intake (TDI) of 100 ng Sn/kg b.w. set by the European Food Safety Authority (EFSA).
CUI ZongYanZHANG KeGangZHOU QunFangLIU JiYanJIANG GuiBin
Decabromodiphenyl ether(BDE209) is poorly absorbed by mammals,and little information is available on the toxicokinetics of BDE209 and its metabolites in fish.In the present study,rainbow trout(Oncorhynchus mykiss) were administered to 100 ng/g and 500 ng/g body wet weight of BDE209 via a single intraperitoneal injection and parent BDE209 and its metabolites were sequentially monitored for 28 days.The results showed that toxicokinetic profiles of BDE209 could be described by the one-compartment model.In the higher dose group(500 ng/g wet weight),the calculated half-life(t1/2) and elimination rate(ke) were 17.7 d and 0.039/d in the liver,and 100.3 d and 0.007/d in the muscle,respectively.Three major methoxylated brominated diphenyl ethers(MeO-BDEs) were detected with 2,2',4,4'-tetrabromo-5-methoxydiphenyl ether(5-MeO-BDE47) being detected in all tissue samples.There was no significant temporal change of 5-MeO-BDE47 concentration in the muscle,whereas an exponential increase was observed in the liver.Therefore,the metabolism rate of BDE209 depended on the administered dose.BDE209 was hardly accumulated in the muscle of rainbow trout,while the liver was a primary metabolic organ.MeO-BDEs were formed via metabolism of BDE209,which probably played a significant role in fish toxicology as a potential indicator.
FENG ChengLian,XU YiPing,ZHA JinMiao,LUO Qian,SHAN XiaoQuan & WANG ZiJian State Key Laboratory of Environmental Aquatic Chemistry
Gold nanoparticles(AuNPs)have been reported to induce faster heat transfer of polymerase chain reaction(PCR)solution to enhance PCR efficiency.AuNPs can also increase the specificity of PCR by functioning analogously to single-stranded DNA binding protein(SSB).However,the simple structure of AuNPs makes it difficult to determine how AuNPs affect PCR efficiency and specificity.This study aimed to elucidate the effect of AuNPs on PCR efficiency by altering the denaturation times and annealing temperatures.In addition,comparative study of the effect of AuNPs on PCR inhibition caused by two competitive primers allowed investigation of the mechanisms of AuNP-enhanced PCR accuracy.Finally,heat-treated salmon sperm DNA was used to evaluate whether AuNPs could eliminate the inhibitory PCR effect caused by DNA impurities.This study demonstrated that enhanced thermal conductivity by AuNPs was the main mechanism for increased PCR efficiency and specificity.AuNPs promoted efficient double-stranded DNA template unwinding and dissociation between mismatched primers,DNA fragments and template,and enhanced PCR efficiency and specificity simultaneously.Thus,this significant finding suggests the future use of AuNP-assisted PCR in different fields,especially in rapid clinical diagnosis and screening by PCR.
LIN YanLI JiaYAO JingLIANG YongZHANG JieZHOU QunFangJIANG GuiBin
