The objective of this study was to evaluate the effects of several different commercial disinfectants on the embryogenic development of Ascaris suum eggs. A 1-ml aliquot of each disinfectant was mixed with approximately 40,000 decorticated or intact A. suum eggs in sterile tubes. After each treatment time (at 0.5, 1, 5, 10, 30, and 60 min), disinfectants were washed away, and egg suspensions were incubated at 25℃ in distilled water for development of larvae inside. At 3 weeks of incubation after exposure, ethanol, methanol, and chlorohexidin treatments did not affect the larval development of A. suum eggs, regardless of their concentration and treatment time. Among disinfectants tested in this study, 3% cresol, 0.2% sodium hypochlorite and 0.02% sodium hypochlorite delayed but not inactivated the embryonation of decorticated eggs at 3 weeks of incubation, because at 6 weeks of incubation, undeveloped eggs completed embryonation regardless of exposure time, except for 10% povidone iodine. When the albumin layer of A. suum eggs remained intact, however, even the 10% povidone iodine solution took at least 5 min to reasonably inactivate most eggs, but never completely kill them with even 60 min of exposure. This study demonstrated that the treatment of A. suum eggs with many commercially available disinfectants does not affect the embryonation. Although some disinfectants may delay or stop the embryonation of A. suum eggs, they can hardly kill them completely.
Animals ; Ascaris suum/*drug effects ; Disinfectants/*toxicity ; Embryo, Nonmammalian/drug effects ; Embryonic Development/*drug effects ; Time Factors

Animals ; Embryo, Nonmammalian ; drug effects ; metabolism ; Ethanol ; toxicity ; RNA, Messenger ; metabolism ; Resveratrol ; pharmacology ; Zebrafish ; Zebrafish Proteins ; metabolism

OBJECTIVEThis study was aimed to investigate the toxic effects of 3 nanomaterials, i.e. multi-walled carbon nanotubes (MWCNTs), graphene oxide (GO), and reduced graphene oxide (RGO), on zebrafish embryos.

METHODSThe 2-h post-fertilization (hpf) zebrafish embryos were exposed to MWCNTs, GO, and RGO at different concentrations (1, 5, 10, 50, 100 mg/L) for 96 h. Afterwards, the effects of the 3 nanomateria on spontaneous movement, heart rate, hatching rate, length of larvae, mortality, and malformations ls were evaluated.

RESULTSStatistical analysis indicated that RGO significantly inhibited the hatching of zebrafish embryos. Furthermore, RGO and MWCNTs decreased the length of the hatched larvae at 96 hpf. No obvious morphological malformation or mortality was observed in the zebrafish embryos after exposure to the three nanomaterials.

CONCLUSIONMWCNTs, GO, and RGO were all toxic to zebrafish embryos to influence embryos hatching and larvae length. Although no obvious morphological malformation and mortality were observed in exposed zebrafish embryos, further studies on the toxicity of the three nanomaterials are still needed.

Animals ; Embryo, Nonmammalian ; Embryonic Development ; drug effects ; Female ; Graphite ; toxicity ; Heart Rate ; drug effects ; Male ; Movement ; drug effects ; Nanotubes, Carbon ; toxicity ; Oxides ; toxicity ; Toxicity Tests ; Zebrafish

OBJECTIVETo evaluate the bio-safety of graphene quantum dots (GQDs), we studied its effects on the embryonic development of zebrafish.

METHODSIn vivo, biodistribution and the developmental toxicity of GQDs were investigated in embryonic zebrafish at exposure concentrations ranging from 12.5-200 μg/mL for 4-96 h post-fertilization (hpf). The mortality, hatch rate, malformation, heart rate, GQDs uptake, spontaneous movement, and larval behavior were examined.

RESULTSThe fluorescence of GQDs was mainly localized in the intestines and heart. As the exposure concentration increased, the hatch and heart rate decreased, accompanied by an increase in mortality. Exposure to a high level of GQDs (200 μg/mL) resulted in various embryonic malformations including pericardial edema, vitelline cyst, bent spine, and bent tail. The spontaneous movement significantly decreased after exposure to GQDs at concentrations of 50, 100, and 200 μg/mL. The larval behavior testing (visible light test) showed that the total swimming distance and speed decreased dose-dependently. Embryos exposed to 12.5 μg/mL showed hyperactivity while exposure to higher concentrations (25, 50, 100, and 200 μg/mL) caused remarkable hypoactivity in the light-dark test.

CONCLUSIONLow concentrations of GQDs were relatively non-toxic. However, GQDs disrupt the progression of embryonic development at concentrations exceeding 50 μg/mL.

Animals ; Behavior, Animal ; Dose-Response Relationship, Drug ; Embryo, Nonmammalian ; abnormalities ; drug effects ; Graphite ; administration & dosage ; chemistry ; toxicity ; Larva ; drug effects ; Quantum Dots ; administration & dosage ; chemistry ; toxicity ; Zebrafish ; embryology

The use of exogenous carbon monoxide releasing molecules (CORMs) provides promise for clinical application; however, the hazard potential of CORMs in vivo remains poorly understood. The developmental toxicity of CORM-3 was investigated by exposure to concentrations ranging from 6.25 to 400 μmol/L during 4-144 h post fertilization. Toxicity endpoints of mortality, spontaneous movement, heart rate, hatching rate, malformation, body length, and larval behavior were measured. CORM-3 disrupted the progression of zebrafish larval development at concentrations exceeding 50 μmol/L, resulting in embryonic developmental toxicity.
Animals ; Carbon Monoxide ; pharmacology ; Cardiotonic Agents ; toxicity ; Dose-Response Relationship, Drug ; Embryo, Nonmammalian ; drug effects ; Embryonic Development ; drug effects ; Organometallic Compounds ; toxicity ; Zebrafish ; embryology ; metabolism

OBJECTIVETo investigate the influence of exposure to different concentrations of ethanol on neural progenitor cells and the differentiation of neurons and glial cells in zebrafish embryos.

METHODSZebrafish embryos were exposed to 1%, 2%, and 2.5% (V/V) ethanol at 5 hpf by adding ethanol to the egg water. In situ hybridization and real-time PCR were used to detect the changes in the mRNA expression profiles of the markers of different cells to examine the effects of alcohol on neural development.

RESULTSThe number of neural precursor cells, neurons and mature glial cells was significantly reduced in the zebrafish embryos following ethanol exposure, and this reduction became more prominent as the ethanol concentration increased. The expression of the early glial marker slc1a3a was down-regulated in the spinal cord but increased in the brain after exposure to increased ethanol concentrations. The expression of the mature glial markers was significantly lowered in response to exposure to increasing ethanol concentrations.

CONCLUSIONSEthanol can reduce neural precursor cells and inhibits neuronal and glial differentiation in zebrafish embryos.

Animals ; Brain ; Cell Differentiation ; drug effects ; Embryo, Nonmammalian ; drug effects ; Ethanol ; adverse effects ; Neural Stem Cells ; drug effects ; Neurogenesis ; drug effects ; Neuroglia ; drug effects ; Neurons ; drug effects ; Spinal Cord ; Zebrafish ; embryology

OBJECTIVE1-Bromo-3-chloro-5,5-dimethylhydantoin (BCDMH) is a solid oxidizing biocide for water disinfection. The objective of this study was to investigate the toxic effect of BCDMH on zebrafish.

METHODSThe developmental toxicity of BCDMH on zebrafish embryos and the dose-effect relationship was determined. The effect of BCDMH exposure on histopathology and tissue antioxidant activity of adult zebrafish were observed over time.

RESULTSExposure to 4 mg/L BCDMH post-fertilization was sufficient to induce a number of developmental malformations, such as edema, axial malformations, and reductions in heart rate and hatching rate. The no observable effects concentration of BCDMH on zebrafish embryo was 0.5 mg/L. After 96 h exposure, the 50% lethal concentration (95% confidence interval (CI)) of BCDMH on zebrafish embryo was 8.10 mg/L (6.15-11.16 mg/L). The 50% inhibitory concentration (95% CI) of BCDMH on hatching rate was 7.37 mg/L (6.33-8.35 mg/L). Histopathology showed two types of responses induced by BCDMH, defensive and compensatory. The extreme responses were marked hyperplasia of the gill epithelium with lamellar fusion and epidermal peeling. The histopathologic changes in the gills after 10 days exposure were accompanied by significantly higher catalase activity and lipid peroxidation.

CONCLUSIONThese results have important implications for studies on the toxicity and use of BCDMH and its analogs.

Animals ; Antioxidants ; metabolism ; Disinfectants ; toxicity ; Dose-Response Relationship, Drug ; Embryo, Nonmammalian ; drug effects ; Hydantoins ; toxicity ; Time Factors ; Water ; chemistry ; Water Pollutants, Chemical ; toxicity ; Zebrafish

To study the chemical constituents of K. oblongifolia, silica gel column chromatography, MCI and Sephadex LH-20 were used to separate the 70% acetone extract of the stems of K. oblongifolia. The structures of the isolated compounds have been established on the basis of physicochemical and NMR spectroscopic evidence as well as ESI-MS in some cases. Twenty compounds were obtained and identified as heteroclitalignan A (1), kadsulignan F (2), kadoblongifolin C (3), schizanrin F (4), heteroclitalignan C (5), kadsurarin (6), kadsulignan O (7), eburicol (8), meso-dihydroguaiaretic acid (9), kadsufolin A (10), tiegusanin M (11), heteroclitin B (12), (7'S)-parabenzlactone (13), angeloylbinankadsurin B (14), propinquain H (15), quercetin (16), kadsulignan P (17), schizanrin G (18), micrandilactone C (19) and (-)-shikimic acid (20). Compouds 1, 5, 8, 11-15, 18 and 20 were isolated from this plant for the first time. Toxicity of compounds 1-10 were evaluated with zebrafish model to observe the effect on its embryonic development and heart function. The results showed that compounds 7, 9 and 10 caused edema of zebrafish embryo and decreased the heart rate of zebrafish, which exhibited interference effect on heart development of zebrafish.
Animals ; Embryo, Nonmammalian ; drug effects ; Guaiacol ; analogs & derivatives ; toxicity ; Kadsura ; chemistry ; Lignans ; toxicity ; Plant Extracts ; toxicity ; Quercetin ; toxicity ; Triterpenes ; toxicity ; Zebrafish ; embryology

OBJECTIVETo investigate the mechanism of retinoic acid (RA) signal in dental evolution, RA is used to explore the influence of the mechanism on neural crest's migration during the early stage of zebra fish embryos.

METHODSWe divided embryos of wild type and transgenic line zebra fish into three groups. 1 x 10(-7) to 6 x 10(-7) mol x L(-1) RA and 1 x 10(-7) mo x L(-1) 4-diethylaminobenzaldehyde (DEAB) were added into egg water at 24 hpf for 9 h. Dimethyl sulfoxid (DMSO) with the concentration was used as control group. Then, antisense probes of dlx2a, dlx2b, and barxl were formulated to perform whole-mount in situ hybridization to check the expressions of the genes in 48 hpf to 72 hpf embryos. We observed fluorescence of transgenic line in 4 dpf embryos.

RESULTSWe obtained three mRNA probes successfully. Compared with DMSO control group, a low concentration (1 x 10(-7) mol x L(-1)) of RA could up-regulate the expression of mRNA (barx1, dlx2a) in neural crest. Obvious migration trend was observed toward the pharyngeal arch in which teeth adhered. Transgenic fish had spreading fluorescence tendency in pharyngeal arch. However, a high concentration (4 x 10(-7) mol x L(-1)) of RA malformed the embryos and killed them after treatment. One third of the embryos of middle concentration (3 x 10(-7) mo x L(-1)) exhibited delayed development. DEAB resulted in neural crest dysplasia. The expression of barxl and dlx2a were suppressed, and the appearance of dlx2b in tooth was delayed.

CONCLUSIONRA signal pathway can regulate the progenitors of tooth by controlling the growth of the neural crest and manipulating tooth development

Animals ; Branchial Region ; Cell Differentiation ; drug effects ; Embryo, Nonmammalian ; drug effects ; embryology ; metabolism ; In Situ Hybridization ; Neural Crest ; drug effects ; Odontogenesis ; Signal Transduction ; Tooth ; drug effects ; embryology ; metabolism ; Tretinoin ; pharmacology ; Zebrafish ; embryology ; genetics ; metabolism

OBJECTIVEDiGeorge/del22q11 syndrome is one of the most common genetic causes of outflow tract and aortic arch defects in human. DiGeorge/del22q11 is thought to involve an embryonic defect restricted to the pharyngeal arches and the corresponding pharyngeal pouches. Previous studies have evidenced that retinoic acid (RA) signaling is definitely indispensable for the development of the pharyngeal arches. Tbx1, one of the T-box containing genes, is proved to be the most attractive candidate gene for DiGeorge/del22q11 syndrome. However, the interaction between RA and Tbx1 has not been fully investigated. Exploring the interaction will contribute to discover the molecular pathways disrupted in DiGeorge/del22q11 syndrome, and will also be essential for understanding genetic basis for congenital heart disease. It now seems possible that genes and molecular pathways disrupted in DiGeorge syndrome will also account for some isolated cases of congenital heart disease. Accordingly, the present study aimed to extensively study the effects of external RA on the cardiac development and Tbx1 expression during zebrafish embryogenesis.

METHODSThe chemical genetics approach was applied by treating zebrafish embryos with 5 x 10(-8) mol/L RA and 10(-7) mol/L RA at 12.5 hour post fertilization (hpf). The expression patterns of Tbx1 were monitored by whole-mount in situ hybridization and quantitative real-time RT-PCR, respectively.

RESULTSThe zebrafish embryos treated with 5 x 10(-8) mol/L RA and 10(-7) mol/L RA for 1.5 h at 12.5 hpf exhibited selective defects of abnormal heart tube. The results of whole-mount in situ hybridization with Tbx1 RNA probe showed that Tbx1 was expressed in cardiac region, pharyngeal arches and otic vesicle during zebrafish embryogenesis. RA treatment led to a distinct spatio-temporal expression pattern for Tbx1 from that in wild type embryo. The real-time PCR analysis showed that Tbx1 expression levels were markedly reduced by RA treatment. Tbx1 expression in the pharyngeal arches and heart were obviously down regulated compared to the wild type embryos. In contrast to 5 x 10(-8) mol/L RA-treated groups, 10(-7) mol/L RA caused a more severe effect on the Tbx1 expression level.

CONCLUSIONThese results suggested that there was a genetic link between RA and Tbx1 during development of zebrafish embryo. RA could produce an altered Tbx1 expression pattern in zebrafish. RA may regulate the Tbx1 expression in a dose-dependant manner. RA could represent a major epigenetic factor to cause abnormal expression of Tbx1, secondarily, disrupt the pharyngeal arch and heart development.

Animals ; Branchial Region ; drug effects ; embryology ; Embryo, Nonmammalian ; drug effects ; Embryonic Development ; drug effects ; Gene Expression Regulation, Developmental ; Heart ; drug effects ; embryology ; T-Box Domain Proteins ; genetics ; metabolism ; Tretinoin ; pharmacology ; Zebrafish ; embryology ; genetics ; Zebrafish Proteins ; genetics ; metabolism