• Korean Journal of Environmental Biology
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• v.39 no.4
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• pp.550-558
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• 2021

In a radiotracer study, the bioaccumulation and efflux of metals in earthworms (Eisenia fetida) exposed to soil spiked with ZnO and Ag nanoparticles (AgNP) were compared to those exposed to soil spiked with ionic Zn and Ag. Additionally, the bioavailability and chemical mobility of nano- and ionic metals in the soil were estimated using the sequential extraction method and compared to the bioaccumulation factor(BAF). The BAF for ZnO (0.06) was 31 times lower than that for Zn ions (1.86), suggesting that ZnO was less bioavailable than the ionic form in contaminated soil. In contrast, the BAFs for two types of AgNPs coated with polyvinylpyrrolidone (0.12) or citrate (0.11) were comparable to those of ionic Ag (0.17). The sequential extraction of metals from the soil suggests that the chemically mobile fractions in the Zn ion treatment were higher(35%) than those (<20%) in the Ag ion treatment, which was consistent with the greater BAFs in the former than the latter. However, the chemical mobility in the ZnO treatments did not predict bioavailability. The efflux rates of Ag (3.2-3.8% d^-1) in the worms were 2-3×those(1.2-1.7% d^-1) for Zn.

• Korean Journal of Animal Reproduction
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• v.22 no.4
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• pp.307-317
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• 1998

This study was to investigate the vitrification method for cryopreservation technique of bovine in vitro fertilization(IVF) embryos. The morphological appearance and viability following vitrification of IVF bovine blastocysts and expanded blastocysts were examined. Embryos obtained 6, 7, 8 or 9 days after IVF were vitrified in both 40% ethylene glycoI(EG) plus 0.3M trehalose and 20% polyvinylpyrrolidone(PVP) in DPBS(ETP, Exp. 1) and ETP solution added 0.375M dextrose (ETPD, Exp. 2). The viability of Days 6, 7, 8 and 9 vitrified /thawed embryos at 24∼48 h culture after thawing was 11.9%, 19.8%, 23.4% and 15.3% in ETP(Exp. 1), and 34.6%, 54.5%, 37.9% and 13.0% in ETPD(Exp. 2), respectively. The viability of vitrified embryos produced from the culture days after IVF did not differ in Exp. 1, but significantly differ in Exp. 2(P＜0.05). The viability of blastocysts and expanded blastocysts significantly differed(P＜0.05) in 15.2% and 23.3%(Exp. 1), and 25.0% and 45.8%(Exp. 2). The result of Exp. 1 was similar to that of Exp. 2 on the viability of embryo according to developmental stages, but ETP solution plus sugar(dextrose) was increased the viability of vitrified embryos. In Experiment 3, The viability of vitrified embryos was not different between 12% and 20% PVP concentrations in ETP solution according to culture days or developmental stages. To investigate the effect of addition of sugar, two type of carbohydrates and a mixture of cryoprotectants for vitrification on the survival of bovine IVF embryos, bovine Days 7 to 9 blastocysts and expanded blastocysts were cryopreserved in either 20% glycerol plus 20% EG, 0.375M sucrose and 0.375M dextrose (GESD, Exp. 4) or 20% glycerol plus 20% EG, 0.3M trehalose and 20% PVP(GETP, Exp. 5) in DPBS. Survival rates of Day 7, 8 and 9 embryos at 24∼48h culture after thawing were 71.4%, 94.6% and 40.5% in GESD, and 59.5%, 81.5% and 62.5% in GETP, respectively. Hatching rates of Day 7, 8 and 9 embryos after thawing were 28.6%, 35.1% and 16.2% in GESD, and 27.0%, 33.3% and 18.8% in GETP, respectively. These results indicates that a mixture of cryoprotectants(glycerol and EG) and addition of sugar can improve the survival rates of the bovine IVF embryos(Day 7 or 8) vitrified, and the expanded blastocyst embryos are more suitable for vitrification than early blastocysts stage.

• Korean Journal of Animal Reproduction
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• v.25 no.3
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• pp.259-267
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• 2001

This study was carried out to investigate on the improvement of fertilizing and developing ability of in vitro matured oocytes from sperm density, motility and PVP(polyvinylpyrrolidone), HA(hyaluronic acid) concentrations, sperm capacitation and intact, free-zona of bovine oocytes obtained by intracytoplasmic sperm injection(ICSI). 1. The fertilization and cleavage rates of bovine oocytes obtained by ICSI treated 0.01, 0.02, 0.03, 0.05% of PVP concentrations were 72.7∼90.9% and 38.5∼54.5%, respectively and these values of 0.02% addition of PVP were higher than other concentrations of PVP 2. The fertilization and cleavage rates of bovine oocytes obtained by ICSI treated 0.01, 0.02% HA and 0.02% PVP + HA concentrations were 72.7%, 40.9% and 81.8%, 54.5% and 83.3%, 37.5%, respectively. and these values of 0.02% addition of PVP + HA were lowe than other concentrations of HA. 3. The fertilization and cleavage rates of bovine oocytes obtained by ICSI treated fresh and frozen sperm were 93.3%, 85.7% and 60.0%, 46.7%, respectively and these values of fresh sperm injection were higher than frozen sperm. 4. The fertilization and cleavage rates of bovine oocytes obtained by ICSI capacitated sperm of heparin, BFF and His methods were 86.7%, 78.9%, 65.0% and 61.9%, 52.6%, 50.0%, respectively. 5. The fertilization and cleavage rates of zona-intact and zona-free bovine oocytes obtained by ICSI were 84.2%, 78.3% and 57.9%, 34.8%, respectively. 6. The fertilization and cleavage rates of bovine oocytes obtained by IVF or ICSI were 63.3∼64.6%, 88.2∼90.0% and 26.7∼29.2%, 52.9∼67.5%, respectively. This ICSI method improved high fertilization rates of bovine oocytes.

• Korean Journal of Animal Reproduction
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• v.23 no.1
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• pp.75-84
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• 1999

This study assessed development in vitro of pronuclear(PN) stage embryos cryopreserved by the method of either vitrification or slow freezing, by using of different cryoprotectants, and equilibration and cooling rate, in rabbit. Ethyleneglycol- ficoll- sucrose(EFS) or ethyleneglycol- polyvinylpyrrolidone - galactose- (EPG-I) for vitrification, and EPG- II for slow freezing as cryoprotectant were used. The pronuclear embryos were exposed to EFS for 0 to 5 min and diluted with D-PBS and/or pre-dilution with 0.5 M sucrose. To examine the viability of frozen-thawed embryos, PN embryos were co-cultured with bovine oviductal epitherial cell(BOEC) for 5 days to hatching blastocyst stage in 39 $^{\circ}C$ 5% $CO_2$incubator. The results obtained were as follows: The dilution with 0.5 M sucrose and D-PBS after the exposure to EFS for 1.0 min resulted in no significant(P＜0.05) decrease in the development of PN embryos to hatching blastocyst(72.0%), compared with controls. The development of PN embryos cryopreserved to hatching blastocyst was not significantly (P＜0.05) different between EFS for 1.0 min(72.0%), EPG-I for 1.0 min(72.0%) and EPG-II for 30 min(66. 7%). The post-thaw development of PN embryos to hatching blastocyst was similarly very low as 6.1% and 11.5% in vitrification with EFS and slow freezing with EPG-II, respectively. The incidence of post-thaw zona-crack in PN embryos cryopreserved by slow freezing with plunging to liquid nitrogen at －35$^{\circ}C$ was signicantly(P＜0.05) higher(25.0%), compared with －85$^{\circ}C$ (1.9%). These results indicated that the rabbit PN embryos could be cryopreserved with either vitrification or slow freezing procedure, and frozen PN embryos could be successfully developed in vitro to haching blastocyst. but the post-thaw development of cryopreserved PN embryos was still very low under the present conditions.