• Proceedings of the Korean Society of Toxicology Conference
• /
• 2003.05a
• /
• pp.56-56
• /
• 2003

The reactivity and toxicity of arsenic compounds depend on the their oxidative states. Exposure to arsenic causes many human health effects, including cardiovascular, hepatic and renal disease, in addition to cancer in kidney, liver, lung, urinary bladder and skin. The cytotoxic effects of arsenite on normal hepatocyte, which most of its biotranfomation takes place. (omitted)

• Korean Journal of Microbiology
• /
• v.29 no.1
• /
• pp.63-68
• /
• 1991

Several arsenic compound-resistant bacteria were isolated from Jung-Rang stream. The isolates, D-3, D-12, and D-14 were characterized phenotypically and genetically, and identified as Serratia liquefaciens, Klebsiella oxytoca, and Klebsiella pneumoniae, respectively. A plasmid of 67kb was found in Klebsiella oxytoca D-12 and designated as pMH12. Transfer of this plasmid from D-12 to E. coli HB101 was occurred, and the resulting transconjugant strains expressed the same level of heavy metal resistance as the donor strain. The physical presence of this plasmid in transconjugant was detected with agarose gel electrophoresis. Arsenite-sensitive derivatives of isolate D-12 were obtained with Mitomycin C treatment which cured pMH12. Antibiotics and heavy metal resistances were also examined to be used as a proper marker for the isolates in gene cloning. Isolate D-12 has resistance to several heavy metal ions such as $Cd^{2+}$ , $Zn^{2+}$ and $Hg^{ 2+}$ Also, all the other arsenite resistant isolates showed resistance to several heavy metal ions and antibiotics.

• Proceedings of the Korean Society of Plant Biotechnology Conference
• /
• 2003.10a
• /
• pp.91-91
• /
• 2003

• Proceedings of the Korean Society of Plant Biotechnology Conference
• /
• 2003.10a
• /
• pp.94-94
• /
• 2003

• Proceedings of the Korean Society of Plant Biotechnology Conference
• /
• 2003.10a
• /
• pp.95-95
• /
• 2003

• Journal of Microbiology and Biotechnology
• /
• v.20 no.1
• /
• pp.169-178
• /
• 2010

The microbial community structure in Thailand soils contaminated with low and high levels of arsenic was determined by denaturing gradient gel electrophoresis. Band pattern analysis indicated that the bacterial community was not significantly different in the two soils. Phylogenetic analysis obtained by excising and sequencing six bands indicated that the soils were dominated by Arthrobacter koreensis and $\beta$-Proteobacteria. Two hundred and sixty-two bacterial isolates were obtained from arsenic-contaminated soils. The majority of the As-resistant isolates were Gramnegative bacteria. MIC studies indicated that all of the tested bacteria had greater resistance to arsenate than arsenite. Some strains were capable of growing in medium containing up to 1,500 mg/l arsenite and arsenate. Correlations analysis of resistance patterns of arsenite resistance indicated that the isolated bacteria could be categorized into 13 groups, with a maximum similarity value of 100%. All strains were also evaluated for resistance to eight antibiotics. The antibiotic resistance patterns divided the strains into 100 unique groups, indicating that the strains were very diverse. Isolates from each antibiotic resistance group were characterized in more detail by using the repetitive extragenic palindromic-PCR (rep-PCR) DNA fingerprinting technique with ERIC primers. The PCR products were analyzed by agarose gel electrophoresis. The genetic relatedness of 100 bacterial fingerprints, determined by using the Pearson product-moment similarity coefficient, showed that the isolates could be divided into four clusters, with similarity values ranging from 5-99%. Although many isolates were genetically diverse, others were clonal in nature. Additionally, the arsenic-resistant isolates were examined for the presence of arsenic resistance (ars) genes by using PCR, and 30% of the isolates were found to carry an arsenate reductase encoded by the arsC gene.

• Journal of the Mineralogical Society of Korea
• /
• v.21 no.4
• /
• pp.425-434
• /
• 2008

Arsenic contamination in soil and groundwater has recently been one of the most serious environmental concerns. This arsenic contamination can be originated from natural or anthropogenic sources. It has been well known that arsenic behavior in geo-environmental is controlled by various oxides or hydroxides, such as those of iron, manganese, and aluminum, and clay minerals. Among those, particularly, iron (oxy)hydroxides are the most effective scavengers for arsenic. For this reason, this study characterized arsenic adsorption of magnetite which is a kind of iron oxide in nature. The physicochemcial features of the magnetite were investigated to evaluate adsorption of arsenite [As(III)] and arsenate [As(V)] onto magnetite. In addition to experiments on adsorption equilibria, kinetic experiments were also conducted. The point of zero charge (PZC) and specific surface area of the laboratory-synthesized magnetite used as an arsenic adsorbent were measured 6.56 and $16.6\;g/m^2$, which values seem to be relatively smaller than those of the other iron (oxy)hydroxides. From the results of equilibria experiments, arsenite was much more adsorbed onto magnetite than arsenate, indicating the affinity of arsenite on magnetite is larger than arsenate. Arsenite and arsenate showed adsorption maxima at pHs 7 and 2, respectively. In particular, adsorption of arsenate decreased with increase in pH as a result of electrical repulsion caused by anionic arsenate and negatively-charged surface of magnetite. These results indicate that the surface charge of magnetite and the chemical speciation of arsenic should be considered as the most crucial factors in controlling arsenic. The results of kinetic experiments show that arsenate was adsorbed more quickly than arsenite and adsorption of arsenic was investigated to be mostly completed within the duration of 4 hours, regardless of chemical speciation of arsenic. When the results of kinetic experiments were fitted to a variety of kinetic models proposed so far, power function and elovich model were evaluated to be the most suitable ones which can simulate adsorption kinetics of two kinds of arsenic species onto magnetite.

• Proceedings of the KSEEG Conference
• /
• 2007.04a
• /
• pp.342-342
• /
• 2007

See Full Text

• Proceedings of the PSK Conference
• /
• 2000.10a
• /
• pp.208.1-208.1
• /
• 2000

• Applied Microscopy
• /
• v.20 no.2
• /
• pp.37-45
• /
• 1990

Ultrastructural and spectrophotometric studies on mitochondrial swelling and contraction were carried out. All mitochondria just after isolated from rat liver showed condensed conformation. When mitochondria were incubated in 0.25 M sucrose only, they were moderately swollen and the absorbance at 520 nm was slightly decreased. Adding ATP to sucrose caused the absorbance to increase and the mitochondria to contract partially. KCl solution of 0.3 M induced marked decrease of absorbance and swelling of mitochondria. When ATP was added to KCl, increase of the absorbance and no contraction of the mitochondria excluding increased electron density of mitochondrial intermembranes were observed. Markedly decreased absorbance and somewhat largely swelled mitochondria in sodium arsenite solution of 0.4 or 1.0 mM were observed. When ATP was added to sodium arsenite, the absorbance increased slightly but mitochondria were more contracted than those in KCl-treated group. Above results indicate that the absorbance may not be correlated to morphological observations in the mitochondrial swelling and contraction.