• Preventive Nutrition and Food Science
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• v.11 no.2
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• pp.120-126
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• 2006

Fish backbone, a major by-product in the fish processing industry, accounts for about 15% of whole fish weight. In this study, recovery of bioavailable calcium from Alaska pollack (Theragra chalcogramma) backbone by-products using enzymatic hydrolysis was investigated. Finely ground fish backbones were hydrolyzed with two proteolytic enzymes (pepsin and protease) to obtain soluble calcium from the by-products. The pepsin digest had a higher degradation efficiency (88%) than protease. Four different concentrations of the fish backbone calcium (100, 250, 500 and 1000 mg/L) prepared by the pepsin digest were treated with $Na_2HPO_4$ at a concentration gradient (0, 1, 2, 4, 8, 10, 15 and 20 mM) to evaluate their solubility, revealing that solubilities of the fish backbone calcium were superior to those of $CaCl_2$ at all the calcium and $Na_2HPO_4$ concentrations. Among the tested concentrations the highest solubility was found in the pepsin digest containing a calcium concentration of 1000 mg/L. Thus, hydrolyzing with pepsin is an effective mode of recovering bioavailable calcium from Alaska pollack fish backbones.

• The Korean Journal of Zoology
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• v.32 no.3
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• pp.281-289
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• 1989

The present study was disigned to determine the concentration of bioavailable steroid hormones in the atretic follicular fluid (FF). The concentradons of progesterone (P), testosterone (T), estradiol (E), androstenedione (A), and 5-$\alpha$ dihydrotestosterone (DIlT) were determined by the established methods of luminescent immunoassay (LIA) or radioimmunoassay (RIA). Concentrations of T, A and Diff in human FF from smail (< 6 mm). medium (8-15 mm), and large (> 15 mm) atretic follicles were significandy higher than those of normal ones (p < 0.01). However, the levels of T, A and DHT in smail atretic foflicle were significandy lower than those found in normal one. The concentrations of P in atretic FF from porcine small (< 3 mm), medium (4-6 mm), and large (> 7 mm) follicles were not different from that of normal ones. However, the concentration of E in atretic forncles of each group was significantly lower than that of normal group (p < 0.001 in each group). On the other hand, the percentages of bioavailable T (BI) in human FF were significandy (p <0.001) higher than those in normal groups. The BT in normal or atretic FF was more than 90 % of total T. The present result demonstrates that the bioavailable androgen, but not E levels in atretic follicles is higher than that of normal one, and that the atretic mechanism might be dependent on the ovarian forncle size in the developmental stage and on the animal model system. Moreover, the present study suggests that the steroids found in the FF are the bioavailable forms and the concentration of BT in FF could be used as one of the valuable criteria classifying the ovarian atretic follicle.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.1
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• pp.75-80
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• 2016

This study was conducted to evaluate effect of chemical amendments on reducing bioavailable fraction of heavy metals in soil along with ecotoxicological effect on earthworms, Eisenia fetida. Three different chemical amendments, lime (L), steel slag (SS), and acid mine drainage sludge (AMDS), were applied with varied application ratio (1, 3, 5%). Heavy metal contaminated soil was mixed with chemical amedments and earthworms, Eisenia fetida, were cultivated for 28 days. Bioavailable fraction of heavy metals (Cd, Cu, Pb, and Zn) extracted with 0.1N HCl was monitored and also, mortality, growth, and metal concentration in earthworm were assessed. Result showed that all three amendments had high efficiency to reduce bioavailable fraction of heavy metals in soil. In particular, lime showed the highest reduction rate of Cu (63.9-87.7%), Pb (7.90-24.65%), and Zn (40.83-77.60%) among three amendments. No mortality of earthworm was observed during experimental period except 3% and 5% AMDS treatment indicating that application of chemical amendments is safe in terms of ecotoxicological aspect. However, no positive correlation was observed between reduction of bioavaialble fraction of heavy metals in soil and earthworms. Overall, application of chemical amendments in agricultural field can be adapted for reducing bioavailable fraction of heavy metals and detoxification in soil.

• Korean Journal of Ecology and Environment
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• v.41 no.1
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• pp.66-72
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• 2008

Total metals, soluble metals, and bioavailable metals were monitored at the sediments of urban lakes located in Seoul, Korea during spring season 2006. The metals measured were zinc, arsenic, chromium, copper, nickel, and cadmium, which are known to be toxic to human health and ecosystems. The main sources of heavy metals in the lakes were urban runoff and atmospheric deposition associated with air pollution in urban areas. Extraction by using a weak electrolyte solution (0.1 M $Ca(NO_3)_2$) was used to predict bioavailability of the metals. Among the six heavy metals studied, copper was the most bioavailable, based the weak electrolyte extraction techniques. Since metal toxicity is related to metal bioavailability, the results were consistent with the high ecotoxicity of copper, compared to other heavy metals. Overall results suggest that there was no direct relationship between total and bioavailable metal concentration, although zinc, copper and cadmium show some relationships.

• Journal of the East Asian Society of Dietary Life
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• v.16 no.1
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• pp.93-98
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• 2006

This study examined whether or not the iron that is accumulated in the recombinant microbes that produce ferritin is bioavailable to rats with iron deficiency. Rats induced with iron deficiency were treated with iron preparations of $Fe(NH_4)_2(SO_4)_2$, horse spleen ferritin, control yeast, and ferritin-producing recombinant yeast for 14 days. The bioavailability of iron was examined by measuring hemoglobin concentration, hematocrit value, and tissue iron stores. Differences between dietary groups were determined by one-way ANOVA, at the level of significance p<0.05. Based on hemoglobin concentration and hematocrit value, iron in $Fe(NH_4)_2(SO_4)_2$, horse spleen ferritin, and ferritin-producing yeast were bioavailable in rats and cured iron deficiency. The efficacy of ferritin and ferritin-producing yeast was confirmed in establishing tissue iron stores after the induction of iron deficiency. The iron sources of ferritin and the ferritin-producing yeast seemed to be as effective for the recovery from iron deficiency as the iron compounds of ferric citrate and ferrous ammonium sulfate. The results suggest that the iron stored in ferritin of the recombinant yeast is bioavailable, and that the recombinant yeast may contribute widely as a source of iron to resolve the global problem of iron deficiency.

• Journal of the korean society of oceanography
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• v.39 no.4
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• pp.243-250
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• 2004

Sediment microcosm experiments were conducted for 14 and 28 days using Zn spiked sediment to examine the changing distribution of bioavailab1e sediment-bound Zn at different SEM (simultaneously extracted metal)-Zn/ AVS (acid volatile sulfide) mole ratios as a function of time and amphipod density. In surficial sediments (0-1cm), AVS concentrations significantly decreased due to bioturbation and oxidation, while SEM-Zn concentrations remained unchanged. As a result, SEM-Zn/AVS ratios in the surface sediment were greater one although the ratios were designed as less than one initially. With increasing SEM-Zn/AVS ratios in surficial sediments, concentrations of potentially bioavailable $MgCl_2$extractable-Zn, NaOAc extractable-Zn and pore water-Zn significantly increased, while concentrations of SEM-Zn were not significantly varied. Results suggested that as AVS concentrations decreased, AVS bound Zn was partitioned to other sediment fractions (i.e. $MgCl_2$ and NaOAc extractable) and the pore water, resulting in changes in Zn bioavailability in surficial sediments. Concentrations of AVS, SEM-Zn and pore water-Zn remained unchanged in the deeper layers (>1 cm) of the sediment.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1998.11a
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• pp.137-141
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• 1998

A chemical has been aging in soil environment is more less bioavailable than freshly added chemical. The amount of bioavailability of the aged chemical is different by bacterial strains. The difference could be depend on physiochemical properties of each strain. Phenanthrene was employed as an aged chemical. Seven bacteria were isolated from activated sludge and petroleum disposed soil. These strains were able to degrade phenanthrene and to grow using phenanthrene as a sole carbon source. According to the result of materialization and chemical extraction experiment, the bioavailable amount of aged phenanthrene which has been aged in Lima loam is different by each bacteria. Several physiochemical properties of each strain were tested to certify correlation with their different amount of bioavailability.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.11
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• pp.1645-1646
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• 2001

The objective of this study was to develop an in vitro digestion technique to estimate bioavailable energy values of different corn hybrids in swine and poultry. A total of 21 samples were investigated; 18 normal corn (NC) and 3 high-oil corn (HOC) hybrids. One step-two enzymes digestion system was introduced to develop the in vitro technique. The gross energy (GE) values of NC hybrids were correlated with the in vitro disappearing energy values (IVE; r=0.85, p<0.01), the in vitro energy digestibilities (IVED; r=0.70, p<0.01), and the in vitro DM digestibilities (IVDM; r=0.55, p<0.05). It appears, however, that IVE values of NC and HOC hybrids were not significantly different according to the one step-two enzyme digestion system. Results of in vivo and in vitro estimates suggested that there was no significant correlation between them in poultry. The IVE value was regressed linearly with ME and DE values in swine with low regression coefficient (34 and 41%, respectively).

• Proceedings of the PSK Conference
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• 2000.04a
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• pp.98.2-98.2
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• 2000

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.24 no.2
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• pp.249-265
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• 2019

A passive sampler is one of the promising methods to easily and more accurately predict the free dissolved and bioavailable concentration ($C_{free}$) in seawater or pore water in sediments. In Europe and the United States, the use of passive samplers has been highly encouraged for more accurate marine environmental risk assessment. However, long deployment time in the field causes problems such as biofouling of the samplers, so there are few studies using passive samplers in Korea. Therefore, we review the principle and basic characteristics of the passive sampler for persistent organic pollutants, and introduce various improvement cases for the field applications of the passive sampler.