Biomedical subjects

In-Sook Lee

Publications and source records attributed to In-Sook Lee.

11 recordsLinked to original sources

PubMed2006

Rhizosphere microbial activity during phytoremediation of diesel-contaminated soil.

To know microbial activity and diesel-removal efficiency influencing through plant roots, we examined the effect of the rhizosphere on phytoremediation of diesel-contaminated soils by alfalfa (Medicago sativa L.). Pots were treated with and without diesel and allowed to stabilize for 7 weeks, at which time four experimental/control groups were prepared: (1) planted diesel-contaminated soil, (2) unplanted diesel-contaminated soil, (3) planted uncontaminated soil, and (4) unplanted uncontaminated soil. Samples of rhizosphere and bulk soils were separately taken from all planted pots. After 7 weeks of alfalfa growth from seeds, the removal efficiencies in rhizosphere and bulk soil samples were 82.5% and 36.5 approximately 59.4%, respectively. The total microbial activity was highest in diesel-contaminated rhizosphere soils. Significantly more culturable soil bacteria and hydrocarbon-degraders were found in diesel-contaminated rhizosphere soil versus unplanted and uncontaminated bulk soil, with a greater increase seen in hydrocarbon-degraders (172-fold) versus general soil bacteria (14-fold). DGGE (Denaturing Gel Gradient Electrophoresis) analysis revealed that the bacterial community structure was most highly influenced by the combined presence of diesel contamination and plant roots (39.13% similarity compared to the control), but that diesel contamination alone had a higher influence (42.31% similarity compared to the control) than the rhizosphere (50.00% similarity compared to the control). Sequence analysis and BLAST searches revealed that all samples were dominated by members of alpha -, gamma -, delta - and epsilon -proteobacteria, and Chloroflexi. The rhizosphere samples additionally contained novel dominant members of alpha -proteobacteria and Cytophaga-Flexibacter-Bacteroides, while the diesel samples contained additional dominant alpha -proteobacteria and the rhizosphere plus diesel samples contained other epsilon -proteobacteria. Collectively, these findings indicate that the presence of plant roots (i.e., a rhizosphere) had a greater effect on bacterial activity in diesel contamination than did the absence of diesel contamination, whereas diesel contamination had a greater effect on bacterial community structure. These novel findings provide new insight into the mechanisms of phytoremediation.

Biodegradation, Environmental↗

PubMed2005

EDTA-assisted phytoextraction of lead from lead-contaminated soils by Echinochloa crusgalli var. frumentacea.

The herbaceous plant Echinochloa crusgalli var. frumentacea is highly resistant to a wide range of heavy metal concentrations. In this study we tested the phytoextraction capacity of E. crusgalli var. frumentacea. Specifically, we compared the effect of EDTA on lead (Pb) accumulation in two groups of plants: those sown in lead contaminated soil and those transplanted to the contaminated soil as seedlings. The result of the time development of the Pb concentrations in the plants in the seedling and seed groups shows that for the seedling group, the effect of adding EDTA to the Pb-contaminated soil was even more pronounced in the shoots than the roots, which showed Pb concentrations 32-fold higher. Compared to the seedling group, the Pb concentrations in the roots of plants in the seed group were approximately 5 times higher in controls and 2 to 10 times higher in the presence of EDTA. Collectively, these results might be considered that EDTA elevates the bioavailability of Pb in soil and this native species is particularly suited to use in Pb phytoextraction.

Biodegradation, Environmental↗

PubMed2005

[Distribution of calcaneal bone density according to the mechanical strain of exercise and calcium intake in premenarcheal girls].

OBJECTIVES: The effects of exercise on bone density have been found to be inconsistent in previous studies. We conducted a cross-sectional study in premenarcheal girls to test two hypotheses to explain these inconsistencies. Firstly, "the intensity of mechanical strain, in terms of the ground reaction force(GRF), has more important effects on the bone mass at a weight-bearing site", and secondly, "calcium intake modifies the bone response to exercise". METHODS: The areal bone mineral density was measured at the Os calcis, using peripheral dual energy X-ray absorptiometry, in 91 premenarcheal girls aged between 9 and 12 years. The intensity of mechanical strain of exercise was assessed by a self-report questionnaire and scored by the GRF as multiples of body weight, irrespective of the frequency and duration of exercise. The energy and calcium intake were calculated from the 24-hour dietary recall. An analysis of covariance(ANCOVA) was used to determine the interaction and main effects of exercise and calcium on the bone density, after adjusting for age, weight, height and energy intake. RESULTS: The difference in the bone density between moderate and low impact exercise was more pronounced in the high than low calcium intake group. The bone density for moderate impact exercise and high calcium intake was significantly higher than that for low impact exercise (p=0.046) and low calcium intake, after adjusting for age, weight, height and energy intake. CONCLUSIONS: Our study suggests that the bone density at a weight-bearing site is positively related to the intensity of mechanical loading exercise, and the calcium intake may modify the bone response to exercise at the loaded site in premenarcheal girls.

Bone Density↗

PubMed2004

Enhanced degradation of 2,4,6-trinitrotoluene (TNT) in a soil column planted with Indian mallow (Abutilon avicennae).

Phytoremediation of soil contaminated with 2,4,6-trinitrotoluene (TNT) was studied by growing Indian mallow (Abutilon avicennae) in a soil column reactor with 2 kg of TNT contaminated soil (120 mgTNT/kg) in the top and 18 kg of uncontaminated soil in the bottom. After 50 d, TNT remaining in the column with Indian mallow was 23.2% of the initial TNT, while 48.1% of the initial TNT remained in the column without Indian mallow. In the TNT contaminated column, the growth of Indian mallow decreased by 32.4% in roots and 34.3% in shoots on a dry weight basis, respectively, compared to the uncontaminated column. However, critical symptoms such as chlorosis and leaf loss were not observed. Of the 76.8% of the TNT that disappeared in the planted column, less than 0.2% of initial TNT was recovered in the shoot and root extracts of Indian mallow. TNT transformation products in plants include unidentified polar intermediates and aminodinitrotoluenes. The results showed that planting Indian mallow in TNT contaminated soil enhanced TNT reduction both by stimulating microbial activity that enhances microbial TNT transformation, and by direct uptake and phytotransformation of TNT.

Journal Article↗

PubMed2004

Effects of crude oil, oil components, and bioremediation on plant growth.

The phytotoxic effects of crude oil and oil components on the growth of red beans (Phaseolus nipponesis OWH1) and corn (Zea mays) was investigated. In addition, the beneficial effects of bioremediation with the oil-degrading microorganism, Nocardia sp. H17-1, on corn and red bean growth in oil-contaminated soil was also determined. It was found that crude oil-contaminated soil (10,000mg/kg) was phytotoxic to corn and red beans. In contrast, obvious phytotoxicity was not observed in soils contaminated with 0-1000 mg/kg of aliphatic hydrocarbons such as decane (C10) and eicosane (C20). Phytotoxicity was observed in soils contaminated with 10-1000mg/kg of the poly aromatic hydrocarbons (PAHs) naphthalene, phenanthrene, and pyrene. It was observed that phytotoxicity increased with the number of aromatic rings, and that corn was more sensitive than red beans to PAH-contaminated soil. Bioremediation with Nocardia sp. H17-1 reduced phytotoxicity more in corn than in red bean, suggesting that this microbial species might degrade PAHs to some degree.

Biodegradation, Environmental↗

PubMed2004

[The differences in quality perceptions, expectations, evaluation, and satisfaction for nursing service between patients and nurses: small-medium sized general hospitals].

PURPOSE: This study was performed to give direction to quality improvement strategies of nursing services by comparing the differences in quality perceptions and satisfaction for nursing services between patients and nurses in small-medium sized general hospitals with 200 beds. METHOD: The subjects, who were 150 inpatients and 162 nurses of 4 general hospitals in a community, answered a self-report questionnaire with a SERVQUAL scale. RESULT: There were differences between patients' and nurses' expectations and perceptions of nursing service and satisfaction. In the service expectation, the highest factor was 'the responsiveness', and in the perceived performance, the highest was the 'assurance'. In addition, overall patients' perceptions on nursing services showed higher than nurses'. There were positive correlations among the expectations and perceptions on nursing service, and satisfaction. The correlation between perception and satisfaction was higher than the correlation between expectations and satisfaction. CONCLUSION: To improve the nursing service quality at small-medium hospitals, strengthening the 'assurance' factor and improving the nursing service support system is needed. Also, this study on nurses' perceived nursing service at small-medium sized hospitals should be duplicated.

Adolescent↗

PubMed2003

Purification and characterization of a copper-binding protein from Asian periwinkle Littorina brevicula.

The Asian periwinkle, Littorina brevicula, is highly resistant to a wide range of heavy metal concentrations and its metal-binding protein(s) are induced in the presence of cadmium (Cd) and zinc (Zn). In this study, we isolated and characterized a novel copper-binding protein (Cu-BP). Following purification by Sephacryl S-100 chromatography, Cu-BP contained an equal amount of Zn in non-exposed physiological conditions. However, Zn is replaced by Cu at the binding site upon addition of excess Cu (100 microM CuCl(2)) to the cytosol or after a long period (60 days) of exposure of the periwinkles to the metal ion (150 microg/l CuCl(2)). The ligand was further purified by DEAE-Sepharose anion-exchange chromatography and C(18) reverse-phase HPLC. The molecular weight of the purified protein was determined as 11.38 kDa by MALDI-TOF MS analyses. This Cu-BP is distinct from common mollusk metallothionein (MT) in that it contains significantly lower number of Cys (8 residues) and high levels of aromatic amino acids, Tyr and Phe. The protein additionally contains His and Met, which are absent in the MT-like Cd-BP of L. brevicula. The finding that Cu-BP in the Asian periwinkle is distinct from MT-like Cd-BP suggests that the timely expression of specific metal-binding proteins allows added protection against each heavy metal in severely polluted conditions.

Amino Acids↗

PubMed2003

Accumulation and elimination of cadmium and zinc in the Asian periwinkle Littorina brevicula.

To elucidate the differences between the detoxification mechanisms of essential metal (Zn) and non-essential metal (Cd) in Littorina brevicula that is highly resistant to a wide range of heavy metal concentrations, Asian periwinkles were exposed to Cd (400 microg/L), Zn (3000 microg/L) and a mixture of both metals. We examined metal accumulation, elimination and subcellular distribution for binding to proteins. The metal concentration in L. brevicula increased gradually with exposure time (up to 70 days), following which accumulated levels reached saturation point. The accumulated Zn content was increased in the presence of Cd, while Cd uptake was decreased when Zn was present. During the depuration period (42 days), Cd was not removed from periwinkles, while Zn was eliminated in a rate of 2.19 microg Zn g(-1) day(-1). This elimination rate was particularly high on exposure to the metal mixture (3.80 microg Zn g(-1) day(-1)). Subcellular distribution studies on Cd and Zn revealed that most Cd (80%) was bound to cytosolic ligand, while more than 75% Zn was distributed in the membrane (insoluble) fraction. An additional difference in sequestering of metal in the cytosol was noted between Cd and Zn; most Cd in the cytosol was bound to metallothionein-like cadmium binding protein, MBP-1 (9.8 kDa), while the profile for Zn distribution revealed the presence of four Zn-binding ligand peaks, specifically, HMW (60 kDa), MBP-1 (9.8 kDa), MBP-2 (5 kDa) and LMW (<1 kDa). Our data confirm that metallothionein-like cadmium binding protein, MBP-1, has the same affinity for Zn, while MBP-2 displays comparatively higher affinity for Zn than Cd.

Animals↗

PubMed2003

Low heavy metal bioavailability in soil at contaminated Korean shooting sites.

The bioavailability of metals at eight military shooting ranges in the Kyungkido and Kangwondo districts in Korea was examined through measurements of the metal content of the tissues of plants growing at the sites. Analysis of the metals in soil samples showed that only a small fraction of the total metal in the soil was soluble (soluble Cd, 0.01-0.43 mg/kg; soluble Cu, 1.63-10.05 mg/kg; soluble Pb, 0.01-414.46 mg/kg; and soluble Zn, 0.01-0.32 mg/kg). Correlation analyses of the levels of Cd, Pb, Cu, and Zn in soil samples and in 14 plant species collected near the sites showed that plant concentrations of Cd and Pb (shoot and root) were significantly correlated to the levels of Cd and Pb in the soil, whereas the concentrations of Cu and Zn in shoot and root tissue showed no correlation with the concentrations of metal in soil. Moreover, no direct relationship was found between the soil microbial respiration activity and soil metal concentration. These results indicate that there are only small amounts of bioavailable metal in the soil at the military shooting ranges studied.

Biological Availability↗

PubMed2002

Heavy metal concentrations and enzyme activities in soil from a contaminated Korean shooting range.

Soil enzyme activities and heavy metal concentrations (Cd, Zn, Cu and Pb) were measured at a general shooting range in South Korea. Total heavy metal concentrations varied with pH, and were negatively correlated with moisture content and organic matter. Most enzyme activities (dehydrogenase, acid phosphatase and beta-glucosidase) and ATP values (measure of biomass) were lower in polluted soils, especially in bald spots contaminated by heavy metals and TNT (2,4,6-trinitrotoluene). These data indicate that concentrated shooting activity inhibits enzyme activity and microbial growth. Soil enzyme activities in richly vegetated spots around the general shooting range were higher (2- to 3-fold) than in bald spots, but lower in areas of heavy metal contamination. Our results demonstrate that the dominant plant species in richly vegetated spots accumulated heavy metals from soils, and suggest certain plants may be useful for decontaminating polluted soil.

Journal Article↗

PubMed2002

Purification and characterization of metallothionein-like cadmium binding protein from Asian periwinkle Littorina brevicula.

Although mussels and oysters in the ocean are known to act as bioconcentrators for contaminants such as heavy metals, their ability to survive in heavily polluted water is relatively limited. The Asian periwinkle, Littorina brevicula, is one species that can accumulate a variety of environmental heavy metals, and the expression of its metal binding protein (MBP) is induced by cadmium. To better characterize this protein and its detoxification mechanism against cadmium, the present work examined the induction of a cadmium binding protein (Cd-BP) in Littorina brevicula exposed to 400 microg/l CdCl(2) for 30 days. The induced Cd-BP was purified by chromatography from the supernatants of homogenized organs (digestive gland, gonad, gill and kidney). This Cd-BP was found to consist of 103 amino acids, was rich in Cys (21 residues), and partial C-terminal sequence obtained by MALDI-TOF MS analysis revealed a Cys-XXX-Cys motif, which resembles a typical feature of mollusc metallothionein (MT). The Cd-BP molecular weight of 9.8 kDa is a little larger than that of other MTs.

Amino Acid Sequence↗