• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• 제2권2호
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• pp.139-148
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• 1998

The charge densities of humic acid and humic extract have been determined by back titration using spectrophotometry as the method of end point detection and several cationic polymers of different charge density(copolymers of acylamide and dimethylaminoethylacrylate and polydiallyidimethylammonium chloride, PDDA), and a cationic indicator o-toluidine blue(o-Tb). The charge densities of humic acid and humic extract obtained depend on the charge densities of cationic polymers used. When the polymers of lower charge density are used, lower apparent charge density values are obtained, but for polymers of high charge density(above 2.5 meq/g), the measured values are almost identical, but also are nearly the same as that obtained for PDDA which has a high charge density(about 6 meq/g). For polymers of lower charge density, it is considered that the optimum dosage does not correspond to 1 :1 charge neutralization between anionic and cationic groups. Polymers of high charge density should be used in order to achieve a complete charge neutralization. As humic acid and humic extract are dissociable acids, their ionization is heavily pH dependent and so higher charge density values are obtaines with increasing pH.

• 미생물학회지
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• 제26권2호
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• pp.122-128
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• 1988

The enzymatic properties of soil cellobiohydrolase were examined and compared with those of cellobiohydrolase-active extracts from soil in the forms of enzyme-humic complex and humicfree enzyme, and cellobiohydrolase partially pruified from Aspergillus niger. The pH optima of soil cellobiohydrolase and cellobiohydrolase-humic complex were greater by 1.5-3.0 pH units than those of cellobiohydrolase in humic-free extract and from A. niger. Soil cellobiohydrolase and cellobiohydrolase-humic complex were remarkably resistant to thermal denaturation and proteolysis. These results confirm that cellobiohydrolase in soil is atable in conditions which rapidly inactivate microbial cellobiohydrolase and that its stability is due to the immobilization of this enzyme by association with humic substances. The Michaelis-Menten constants (Km) for soil, cellobiohydrolase-humic complex, humic free extract and cellobiohydrolase from A. niger were 22.1mg/ml, 11.3mg/ml, 10.6mg/ml and 4.5 mg/ml of Avicel, respectively.

• Advances in environmental research
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• 제1권3호
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• pp.211-221
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• 2012

Bromadiolone (BRD), a second generation anticoagulant often applied to the living environment to control rodents, is usually considered to have low environmental toxicity due to its poor solubility in water. In this study of the effect of humic acid (HA) on BRD using electronic absorption spectroscopy, it has been observed that BRD is appreciably solubilized even in low concentrations of aqueous HA solutions. The BRD solubilization efficiency of aqueous HA was found to be $2.39{\pm}0.14$ ($4.53{\pm}0.26{\mu}M\;ppm^{-1}$). It was also seen that BRD is reasonably solubilized in aqueous extract of farm soil.

• 미생물학회지
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• 제34권3호
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• pp.132-136
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• 1998

자연환경의 미생물군집을 분자생태학적 방법으로 분석하기 위해서는 오염되지 않은 순수한 핵산의 분리가 필요하다. 해양퇴적물에서 핵산을 추출할 때 같이 추출되는 부식물질(humic substances)은 핵산중폭반응을 저해하기 때문에, 이를 제거하기 위한 네 가지의 방법, 아가로즈젤 전기영동후 용출, Sephadex G-75 젤, Hydroxyapatite 젤, 그리고 PVPP(poluvinylpolypyrrolidone) microspin column 방법에 대해 그 효율성을 비교하였다. 조산된 방법 중에서 PVPP microspin column을 이용하면 건조 퇴적물 1g당 $4.8{\mu}g$의 순수한 DNA를 신속하고 간편하게 얻을 수 있었고, 이 방법으로 분리된 DNA를 PCR의 주형으로 사용한 결과 16S rRNA 유전자의 거의 전 범위에 해당하는 1.5 kb 크기의 PCR 산물을 얻을 수 있었다.

• 한국토양비료학회지
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• 제46권5호
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• pp.391-398
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• 2013

Soil organic carbon (SOC) has the potential to promote the soil quality for sustainability and mitigation of global warming. There is little information on organic carbon composition despite of having resistance of carbon degradation in soil. In this study, to understand the effect of volcanic ash on organic carbon composition and quantity in soil, we investigated characteristics of volcanic soil and compared organic carbon composition of soil and humic extract by using $^{13}C$-CPMAS-NMR spectra under soil profiles of Namweon series in Jeju. SOC contents of inner soil profiles were 134.8, 101.3, and 27.4 g C $kg^{-1}$ at the layer of depth 10-20, 70-80 and 90-100 cm, respectively. These layers were significantly different to soil pH, oxalate Al contents, and soil moisture contents. Alkyl C/O-alkyl C ratio in soil was higher than that of humic extracts, which was decreased below soil depth. Aromaticity of soil and humic extract was ranged from 29-38 and 24-32%, which was highest at the humic extract of 70-80 cm in soil depth. These results indicate that the changes of SOC in volcanic ash soil resulted from alteration of organic composition by pyrolysis and stability of organic carbon by allophane in volcanic ash soil.

• Journal of Microbiology
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• 제34권3호
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• pp.229-235
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• 1996

Microgram quantities of DNA per gram soil were recovered with SDS- based and freeze-and thaw procedures. The average DNA fragment size was > 23 Kb. This method generated minimal shearing of extracted DNA. However, the DNA extracts still contained considerable amounts of humic impurities sufficient to inhibit PCR. Several approaches were used to reduce the interferences with the PCR (use of CTAF in extraction step, Elutip-d column purification, addition of BSA to PCR buffer) to accomplish PCR with DNA extract as a template. Most of the DNA extracts were not digested completely by restriction endonuclease, and CTAB-TREATED ane Elutip-d column purified DNA extracts were partially digested. Regarding as restriction enzyme digestion, all PCRs failed to amplify 16S rRNA gene fragments in the DNA extracts. In the case of DNA extracts only where BSA was added to PCR buffer, PCR was successfully conducted whether the DNA extracts were treated with CTAB or purified with columns. However, these two treatments were indispensable for humic impurity-rich DNA extracts to generate the PCR-compatible DNA samples. Direct extraction of DNA, coupled with these procedures to remove and relieve interferences by humic impurities and followed by the PCR, can be rapid and simple method for molecular microbiological study on soil microorganisms.

• Journal of Plant Biology
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• 제37권3호
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• pp.301-308
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• 1994

The individual and combined effects of acidic rain, Mg deficiency (-Mg) and Al surplus (＋Al) on the growth of shoots and roots of pitch pine seedlings and the effect of humic substances (Lit) on Al toxicity were investigated. The growth of height and dry matter were not significantly less for pitch pine seedlings sprayed with simulated acid rain (SAR) of pH 3.5 than for those sprayed with SAR of pH 5.6. But treatments of Al and ＋Al-Mg in soil solution reduced the growth of seedlings in terms of height of shoots, and dry matter of shoots or roots. Effect of Mg deficiency on the growth of seedlings was apparent only when Al was treated simutaneously. The growth of seedlings, regardless of rain pH, decreased in the following order: control=-Mg>Lit＋Al>＋Al>＋Al-Mg. Treatments of Al and ＋Al-Mg in soil solution reduced the total length of secondary and teritary roots of seedlings regardless of rain pH, and decreased in the following order: the primary root

• Bulletin of the Korean Chemical Society
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• 제31권12호
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• pp.3755-3759
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• 2010

A on-line SPE (solid phase extraction)-HPLC preconcentration method was developed for the determination of phenolic compounds at trace levels in environmental water sample. XAD-4 and Dowex 1-X8 were used as sorbent in the on-line SPE-HPLC method for the selective enrichment of nine phenolic compounds, which are included in the priority pollutants list of the US EPA. Also alumina prefiltering considerably reduced the amount of interfering peaks due to humic substances that could accumulated due to the preconcentration step and prevent quantification of polar phenolic compounds in environmental water samples. This method was used to determine the phenolic compounds in tap and river water and superiority to the US EPA 625 method in its enrichment factor, pretreatment time, recoveries, and detection limit. The limits of detection were in the range of $0.3-0.9\;{\mu}g/L$ in tap water sample.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1997년도 춘계학술발표회논문집(2)
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• pp.439-444
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• 1997

In order to investigate organic association of fallout cesium, strontium and plutonium in the soil, soil samples influenced by fallout from nuclear weapon testings were treated with alkali (0.1 M-sodium hydroxide solution) to extract organic acids. After extraction, the resultant three fractions (sedimentary residue, humic and fulvic acid fractions) were subjected to the r-ray spectrometric analysis for $^{137}$ Cs, and radiochemical analysis for gosr and $^{239,240}$Pu. Alkali extraction experiments showed that a lot of $^{ 239,240}$Pu was extracted to organic acids from the soil samples, whereas most of $^{137}$ Cs and $^{90}$ Sr remained in residual fraction. Less than 10% of the total $^{137}$ Cs and $^{90}$ Sr was found in the organic fraction. The concentrations of $^{137}$ Cs and $^{90}$ Sr associated with humic fractions were higher than those with the corresponding fulvic fractions. It was found that more than 40% of the total $^{239,240}$Pu was associated with the organic fraction of soils. In contrast with $^{137}$ Cs and $^{90}$ Sr, $^{239,240}$Pu associated with vulvic fractions was much higher than in humic fractions.

• Journal of Plant Biotechnology
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• 제46권2호
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• pp.114-118
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• 2019

Efficient protocol for plant shoot regeneration of Brassica juncea L. CZERN was established by using organic media components and growth stimulating factors of the vermicompost and coelomic fluids. Formulated organic plant tissue culture media (Vermicompost (30%) extracts supplemented with 20 mL/L coelomic fluid) have shown maximum shoot regeneration when compared with the Murashige and Skoog (MS) medium, which were supplemented with 1 mg/L 6-benzyladenine (BA) and 0.1 mg/L of Naphthaleneacetic acid (NAA). Cotyledon explants produced the highest shoot regeneration frequency from fourday-old germinated seedlings in comparison with non-germinated seedlings. The vermicompost extracts have proved to be the best organic plant growth media to induce shoots from cotyledons compared to the MS media. Statistically significant difference (P = 0.008) for the root length, shoot length (P=0.000350) and the leaves (P=0.375) of the mustard plantlets were analyzed successfully. The survival rate was 98% in the mustard cotyledons on the Vermicompost extract media and 63% on MS media respectively. The coelomic fluid also is much suitable to induce shoots from cotyledons at lower concentrations. It was also shown that the vermicompost extract, which comprised of humic acids along with coelomic fluid, affected shoot regeneration from the cotyledons. An efficient and organic shoot regeneration study was standardized and it can be applicable in the improvement of the economically important crops.