氯化镉、灭多威和硝基苯对日本青鳉(Oryzias latipes)行为抑制的生物应急监测

研究了氯化镉、灭多威和硝基苯对孵化以后7d左右日本青鳉(Oryzias latipes)行为毒性。结果表明,在不同污染物中,随暴露浓度的增加,第1尾日本青鳉产生行为抑制的时间逐渐缩短,并且半数行为抑制时间(time ofhalf behavior inhibition,THBI,Y)随暴露浓度(X)呈现幂指数关系Y=aXb,其中20<a<28,-1.2<b<-0.8。实验结果表明基于日本青鳉THBI分析,能初步实现水体突发性污染事故污染水平的应急监测,从而为污染事故应急预案提供支持。

Accumulation of Lathenum with Various Species in Oryzias Latipes Body

The accumulation and absorption kinetics of La by fish (Oryzias latipes) from both water and food were tested in fresh water. The effects of La concentration in water and food and the existence of fulvic acid on the absorption were investigated. It was demonstrated that the amount of La accumulated in fish increases with the increase in La concentration in water and food and exposure duration, which the normal physiological activity of fish was inhibited. With fulvic in the system, the absorption rate decreases significantly indicating that the fulvic combined La is not available to the fish uptake.

Acute toxicity of DMAH to Oryzias latipes as modified by some influential factors

As a new insecticide,less information about the aquatic biological toxicity of DMAH[N-（2,4-dimethylphenyl）-N’-methylamidine hydrochloride]is known.Acute 96h static bioassayswere conducted with Oryzias latipes to assess the toxicity of DMAH and the influence of environ-mental factors.The results indicated that,at 23℃,the 24h,48h and 96h LC50are 14.6 mg/L,13.06 mg/L and 12.39 mg/L,respectively,the safe concentration（SC）of DMAH to Oryzias latipes is1.16-1.32 mg/L.The changes of temperature,pH value and hardness of water will significantlyinfluence the toxicity of DMAH to fish.

Toxicity Effects of 1,4-Dinitrobenzene on Oryzias Latipes

Dinitrobenzene（1,4-DNB） is one of the preferential toxicants stipulated by OECD and EPA of USA. With Oryzias latipes, which were chosen as the acceptors according to the international standard, the acute, subacute and accumulative toxicity experiments were conducted. The threshold mass concentration of O.latipes was 1.360 mg/L. The subacute experiment showed that O.latipes were hardly affected when the mass concentration of 1,4-DNB was 0.0292 mg/L, but were significantly affected when the mass concentration of 1,4-DNB was 0.0420, 0.0608 or 0.0875 mg/L in contrast to the control sample（P<0.05）. The accumulative rate（K） was 1.21. This shows that there are significant accumulative actions of 1,4-DNB in fish. When the mass concentration of 1,4-DNB is in the range of 0.0320.320 mg/L, the higher the 1,4-DNB concentration, the more strongly the Na +/K +-ATPase is inhibited. The calculated IC 50 values in gill, kidney and liver of O. latipes are 0.128, 0.132 and 0.428 mg/L, respectively.

Transgenerational bone toxicity in F3 medaka (Oryzias latipes) induced by ancestral benzo[a]pyrene exposure: Cellular and transcriptomic insights

Benzo[a]pyrene(BaP),a ubiquitous pollutant,raises environmental health concerns due to induction of bone toxicity in the unexposed offspring.Exposure of F0 ancestor medaka(Oryzias latipes)to 1μg/L BaP for 21 days causes reduced vertebral bone thickness in the unexposed F3 male offspring.To reveal the inherited modifications,osteoblast(OB)abundance and molecular signaling pathways of transgenerational BaP-induced bone thinning were assessed.Histomorphometric analysis showed a reduction in OB abundance.Analyses of the miRNA and mRNA transcriptomes revealed the dysregulation of Wnt signaling(frzb/ola-miR-1–3p,sfrp5/ola-miR-96–5p/miR-455–5p)and bone morphogenetic protein(Bmp)signaling(bmp3/ola-miR-96–5p/miR-181b-5p/miR-199a-5p/miR-205–5p/miR-455–5p).Both pathways are major indicators of impaired bone formation,while the altered Rank signaling in osteoclasts(c-fos/miR-205–5p)suggests a potentially augmented bone resorption.Interestingly,a typical BaP-responsive pathway,the Nrf2-mediated oxidative stress response(gst/ola-miR-181b-5p/miR-199a-5p/miR-205),was also affected.Moreover,mRNA levels of epigenetic modification enzymes(e.g.,hdac6,hdac7,kdm5b)were found dysregulated.The findings indicated that epigenetic factors(e.g.,miRNAs,histone modifications)may directly regulate the expression of genes associated with transgenerational BaP bone toxicity and warrants further studies.The identified candidate genes and miRNAs may serve as potential biomarkers for BaP-induced bone disease and as indicators of historic exposures in wild fish for conservation purposes.

Efficient gene editing in a medaka(Oryzias latipes)cell line and embryos by SpCas9/tRNA-gRNA

Generation of mutants with clustered regularly interspaced short palindromic repeats(CRISPR)/CRISPR-associated protein 9(Cas9)is commonly carried out in fish species by co-injecting a mixture of Cas9 messenger RNA(mRNA)or protein and transcribed guide RNA(gRNA).However,the appropriate expression system to produce functional gRNAs in fish embryos and cells is rarely present.In this study,we employed a poly-transfer RNA(tRNA)-gRNA(PTG)system driven by cytomegalovirus(CMV)promoter to target the medaka(Oryzias latipes)endogenous gene tyrosinase(tyr)or paired box 6.1(pax6.1)and illustrated its function in a medaka cell line and embryos.The PTG system was combined with the CRISPR/Cas9 system under high levels of promoter to successfully induce gene editing in medaka.This is a valuable step forward in potential application of the CRISPR/Cas9 system in medaka and other teleosts.

Record of Leptometopa latipes(Diptera:Milichiidae)from a human cadaver in the Mediterranean area

In forensic entomology,insects are used mainly to obtain information about the time since death.This information is obtained studying the developmental rate of the first colonizers,principally species in the families Calliphoridae,Sarcophagidae,Muscidae,Stratiomyidae and Phoridae.However,species belonging to other families can provide information about body transfer or the season of the death.Among them Milichiidae are flies rarely reported from human cases despite the larvae of some species are known as saprophagous feeding on plant and animal decomposing matter.A potential cause of the lack of records of these species from forensic cases can be related with the paucity of descriptions and illustrations of the immature stages.In this article,the entomological samples collected from a human body found inside an apartment in a Maghreb country,in Northern Africa,is reported and Leptometopa latipes(Diptera:Milichiidae)is described in detail.Molecular analysis is also reported to confirm the morphological analysis.

Knockout of lipoprotein lipase with CRISPR/Cas9 causes severe developmental defects and affects lipid deposition in Japanese medaka(Oryzias latipes)

In mammals,lipoprotein lipase(LPL)has been found to play an important role in lipid mentalismand deposition.LPL deficiency in humans(Homo sapiens)and mice(Mus musculus)tends to cause hypertriglyceridemia.The lpl gene is not expressed in adult mammalian liver,but is in adult fish liver.The functions provided by the lpl gene are diverse in vertebrates.Here,we knocked out the lpl gene in Japanese medaka(Oryzias latipes)with the CRISPR/Cas9 system.The lpl-knockout(KO)homozygous individuals showed severe developmental defects with an extremely emaciated and deformedbody and onlyaccounted for about5%of the F2fish.This is consistentwiththefindings inmicebut disaccords with the results for zebrafish(Danio rerio).Compared with wild-type(WT)madaka,the mRNA level of lpl in lpl-KO heterozygous mutant was significantly higher in the muscle,showed no significant difference in the liver,and was significantly lower in the heart.Under lpl heterozygous deficiency,the relative area of Oil RedO and triglycerides(TG)level in the liver,heart and muscle tissue covaried with levels of lpl mRNA in medaka.The lpl heterozygous deficiency did not affect the levelsofTG,low-density lipoprotein cholesterol(LDL-C),high-density lipoprotein cholesterol(HDL-C)and total cholesterol(TC)in the plasma of medaka,which is inconsistent with the findings in mammals.In general,the lpl gene plays an important role in the growth and development and is closely related to lipid deposition of medaka.