• Microbiology and Biotechnology Letters
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• v.35 no.2
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• pp.112-117
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• 2007

Protein kinases play very important role for maintaining viability in prokaryote and eukaryote. The metabolism of prokaryotic cell is generally regulated by bacterial two-component regulatory systems that are composed of histidine and asparitic acid kinases, however, some eukaryotic signal transduction system such as, serine and threonine kinases, have been also found to be involved in the regulation of morphogenesis and physiological differentiation in Streptomyces. Streptomyces griseus, a streptomycin producer, was expected to have varlous types of eukaryotic-type serine/threonine protein kinases, controlling morphogenesis. Thus, many steps of chromatographies were applied to isolate serine and threonine kinases from S. griseus IFO13350. The immunoaffinity steps using anti-phosphoserine, anti-phosphothreonine, and anti-phosphotyrosine agarose column chramatographies were successfully introduced to identify eukaryotic protein kinases from S. griseus IFO13350. Eight proteins with the expected molecular weight of 14, 29, 31, 35, 40, 52, 56, and 60 kDa, were identified on SDS-PAGE, and the their kination activity was confirmed by nonradioactive protein kination assay using FITC-labeled peptide as the substrate.

• Journal of Food Hygiene and Safety
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• v.11 no.2
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• pp.149-157
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• 1996

A procedure for the determination of Aflatoxins in food and grains which utilizes reversed phased liquid chromatographic (LC) analysis with postcolumn derivatization by an electrochemical cell and determination with a fluorescence detector has been evaluated. The LC mobile phase was water-acetonitrile-methanol (6+2+2) with 1mM KBr and 1 mM HNO3 which gave baseline separation for the four Aflatoxins (AfB1, AfB2, AfG1, AfG2). The electrochemical cell set at 7V, generated bromine and derivatized aflatoxins B1 and G1, The derivatives were detected by the fluorescence detector. The aflatoxins in naturally contaminated corn samples were isolated by three different cleanup procedures: the AOAC method I column(CB method), a rapid filtrate column (Romer's column), and an immunoaffinity column. The final extract were quantitated with fluordensitometric TLC and the LC postcolumn derivatization techniques. The results were quite similar, however the LC technique showed less interferences and could be automated. Samples of corn, raw peanuts, peanut butter and dried dates were also analyzed successfully with this procedure.

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.290.3-291
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• 2003

To increase detection sensitivity for multi-DDT residues (o,p-/p,p-DDT, o,p-/p,p-DDE, o,o-/o,p-DDD) analysis, a highly selective sample clean-up method was introduced prior to GC/MS analysis using immunoaffinity column. The immunoaffinity matrix was prepared by coupling IgG fraction of DDT antiserum to cyanogens bromide activated Sepharose 4B. Three DDT antisera (DDA-1, DDHP-2, DDCP-3) were test for affinity column ligand that obtained by imunizing respective DDT immunogen to rabbits, and IgG was purified using protein A affinity purification. (omitted)

• Clinical and Experimental Reproductive Medicine
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• v.17 no.1
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• pp.71-80
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• 1990

New immunoassay systems for the detection of anti-sperm antibodies were developed. For this, sperm surface protein was purified by the immunoaffinity column prepared by the coupling of rabbit anti-human IgG antibodies to Sepharose-4B. Fraction eluted by tris-HCI buffer containing SDS showed a single band having molecular weight of about 60KD on electrophoresis. Enzyme HRP labelled goat anti-human IgG and chemiluminescence aminobutylethyl-isoluminol(ABEI) labelled rabbit anti-human IgG were used for ELISA and CIA, respectively. These two labelled conjugate bound well with human IgG. When serum dilution curves were made to titrate positive serums, two kinds of curves with steep and sluggish slopes were obtained Serum samples were categorized into 3 groups: positive, weak positive and negative based on slope of curve and O.D. values at 1:160 dilution of serum. When ELISA and CIA were compared to conventional method Kibrick test by the determinations of 62 male serums with different diagnosis, the results of ELISA and CIA agreed well, but both disagreed with that of Kibrick test. This study showed that purified sperm surface antigen can be used to develope solid-phase immunoassay systems such as ELISA and CIA which may eliminate the problems encounted the immobilization of living sperm in other tests.

• Journal of Food Hygiene and Safety
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• v.35 no.3
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• pp.252-260
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• 2020

This study was conducted to improve the standard method for vitamin B₁₂ and biotin contained in foods for special dietary uses to ensure the specificity of the complex matrix properties of foods. For the food code, the test method was improved to determine vitamin B₁₂ and biotin by high-performance liquid chromatography (HPLC)-UV using column-switching after concentration using immunoaffinity column. The immunoaffinity columns contain a gel suspension of monoclonal antibody specific to the vitamin of interest so that it can be used to concentrate the vitamin B₁₂ and biotin and remove interferences from the food extracts. Moreover, validation of advanced new methods was carried out to support the suitability of the proposed analytical procedure (specificity, linearity, detection limits (LOD), quantitative limits (LOQ), accuracy, and precision). The improved analytical method is being used to monitor relevant food items on sale. The results of this study showed that the new analytical method is suitable and appropriate for managing food intended for special dietary uses.

• Korean Journal of Food Science and Technology
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• v.24 no.4
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• pp.367-370
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• 1992

Aflatoxins are highly carcinogenic agents consistantly found as contaminants in human food supplies in many areas of the world and epidemiologically linked to incidence of human liver cancer. To examine the carcinogenic action of aflatoxin $B_1$, aflatoxin $B_1-DNA$ adducts were chemically synhtesized with the reaction of 20 mg calf thymus DNA, and 8 mg standard aflatoxin $B_1$. Since DNA molecule was too large for analysis, it was fragmented by acid hydrolysis and heat. The fragmented aflatoxin $B_1-DNA$ adducts were selectively concentrated by immunoaffinity column procedure and confirmed by HPLC method. The main component was aflatoxin $B_1-guanine$ adduct, which was quantatively measured as 5.2 mg aflatoxin $B_1$.

• Korean Journal of Food Science and Technology
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• v.36 no.1
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• pp.158-161
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• 2004

To determine rapid and reliable analytical method for ochratoxin A detection in cereal-based Korean traditional foods, ochratoxin A content was measured by high-performance liquid chromatography (HPLC) with immunoaffinity column clean-up. Recoveries of ochratoxin A in tested samples ranged from 68.4 to 85.3%. Occurrences of ochratoxin A were 15, 10, and 5% for Kochujang, Deonjang, and Kanjang, respectively. None was detected in Sunsik (mixed cereals). Average levels of ochratoxin A ranged from $0.5\;to\;1.3{\mu}g/kg$, lower than maximum residue level of $5-50{\mu}g/kg$ of ochratoxin A recorded in foreign food code.

• Korean Journal of Food Science and Technology
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• v.39 no.5
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• pp.488-493
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• 2007

A survey for total aflatoxins (aflatoxins $B_1$, $B_2$, $G_1$, and $G_2$) was conducted on 245 cereals and processed cereal products, and 148 nuts and processed nut products in Korea, for a total of 393 commercialized ed samples. The total aflatoxins were quantified by the immunoaffinity column clean-up method with high performance liquid chromatography (HPLC) - fluorescence detection (FLD), and were confirmed by liquid chromatography tandem mass spectrometry (LC-MS/MS). Total aflatoxins(AFs) were detected in 37 samples (9.4% incidence), including 2 millet samples, 1 mixed cereal (sunsik), 1 powdered malt sample, 2 processed cereal products, 6 peanut samples, 22 peanut butter samples, and 1 sample each of almonds, adlay tea, and a processed nut product. The contamination levels were $0.04-2.65{\mu}g/kg$ for aflatoxin $B_1$, and $0.04-5.51{\mu}g/kg$ for total aflatoxins. Finally, LC-MS/MS analysis of the contaminated samples was conducted to confirm the detected aflatoxins, and all 37 samples showing aflatoxins by HPLC-FLD were confirmed by LC-MS/MS.

• Food Science of Animal Resources
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• v.41 no.2
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• pp.335-342
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• 2021

Vitamin B12 deficiency may lead to serious health issues in both infants and adults. A simple analytical method involving sample pretreatment with enzyme, followed by cyanide addition under acidic conditions; separation on an immunoaffinity column; and high-performance liquid chromatography (HPLC) was developed for the rapid detection and quantitation of vitamin B12 in powdered milk. Detection limit and powdered milk recovery were determined by quantitative analysis. The limits of detection and quantitation were 2.71 and 8.21 ㎍/L, respectively. Relative standard deviations of the intra-day and inter-day precisions varied in the ranges of 0.98%-5.31% and 2.16%-3.90%, respectively. Recovery of the analysis varied in the range of 83.41%-106.57%, suggesting that the values were acceptable. Additionally, vitamin B12 content and recovery in SRM 1849a were 54.10 ㎍/kg and 112.24%, respectively. Our results suggested that the analytical method, including the sample pretreatment step, was valid. This analytical method can be implemented in many laboratory-scale experiments that seek to save time and labor. Therefore, this study shows that immunoaffinity-HPLC/ultraviolet is an acceptable technique for constructing a reliable database on vitamin B12 in powdered milk containing starch as well as protein and/or fat in high amounts.

• Journal of the Korean Society of Food Culture
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• v.35 no.3
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• pp.278-284
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• 2020

In this study, biotin (vitamin B7) contents of frequently consumed foods in Korea were determined by using immunoaffinity column in conjunction with high-performance liquid chromatography (HPLC). The biotin contents of 24 foods of plant origin and 27 foods of animal origin were selected. The highest biotin contents in frequently consumed foods of plant origin were found in red beans (Huinguseul; 11.475 ㎍/100 g). On the other hand, biotin was not detected in any varieties of sorghum. For frequently consumed foods of animal origin, salted pollack roe (7.486 ㎍/100 g) showed the highest biotin content. However, beef and fish contained less biotin. All biotin analyses were conducted under analytical quality control. The limits of detection and limits of quantification of biotin were 0.007 and 0.023 ㎍/100 g, respectively, and the accuracy/recovery percentage was 95.35-105.02%. The precision values were 4.041% (repeatability) and 3.835% (reproducibility). Taken together, our data provide reliable data on the biotin contents of frequently consumed foods in Korea.