• Journal of Life Science
• /
• v.26 no.2
• /
• pp.164-173
• /
• 2016

Isotocin (IT), a nonapeptide homolog of oxytocin in mammals, has been suggested to be involved in physiological processes including social behaviors, stress responses, and osmoregulation in teleost fish. To study its structure and function, the gene encoding the IT precursor was cloned from the genomic DNA and brain cDNA of the cinnamon clownfish, Amphiprion melanopus. The IT precursor gene consists of three exons separated by two introns, and encodes an open reading frame of 156 amino acid (aa) residues, comprising a putative signal peptide of 19 aa, a mature IT protein of 9 aa, a proteolytic processing site of 3 aa, and 125 aa of neurophysin. Tissue-specific analysis of the IT precursor transcript indicated its expression in the brain and gonads of A. melanopus. To examine its osmoregulatory effects, the salinity of the seawater (34 ppt) used for rearing A. melanopus was lowered to 15 ppt. Histological analysis of the gills indicated the apparent disappearance of an apical crypt on the surface of the gill lamella of A. melanopus, as pavement cells covered the surface upon acclimation to the lower salinity. The level of Na⁺/K^+-ATPase activity in the gills was increased during the initial stage of acclimation, followed by a decrease to its normal level, suggesting its involvement in osmoregulation and homeostasis. The only slight increase in the level of IT precursor transcript in the A. melanopus brain upon low-salinity acclimation suggested that IT played a minor role, if any, in the process of osmoregulation.

• Journal of Life Science
• /
• v.26 no.2
• /
• pp.253-258
• /
• 2016

In this study, nano-micelled curcumin was produced with natural sea salt with a view to comparing the in silico molecular binding affinity of pure curcumin compound to the active site of transthyretin. Using an optical light microscope and an electron microscope, it was found that the structure of the surface and the cross-section of nano-micelled curcumin was significantly different from natural sea salt. In particular, the crystal structure and nano-components in the nano-micelled curcumin were united, and the layer was more strongly stabilized than untreated salts. In the virtual 3D structure, in silico molecular docking study, the ligand binding affinity of nano-micelled curcumin to the transthyretin active site was found to be higher than that of pure curcumin. In addition, a nano-micelled curcumin formula interacted with more amino acid residues of transthyretin domains. The pharmacophore feature of the nano-micelled curcumin also showed more condensed and constrained features than normal curcumin. These results suggest that nano-micelled curcumin may effectively bind to and stabilize transthyretin, thereby regulating transthyretin-related physiological diseases. Collectively, the nano-micelled curcumin process suggests that normal curcumin can be modified more efficiently into the novel bio-functional chemical formula to stabilize the transthyretin structure. Therefore, the nano-micelled curcumin process can be applied to the field of the regulation of Alzheimer's disease.

• Journal of Life Science
• /
• v.22 no.3
• /
• pp.340-346
• /
• 2012

Bacterial resistance to antibiotics and residues of antibiotics in poultry products have encouraged the use of probiotics, prebiotic substrates, and synbiotic combinations of prebiotics and probiotics as alternative approaches to the use of antibiotics in poultry. The present study was carried out to evaluate the effect of a new probiotic CS61 culture on growth performance, feed conversion efficiency, and safety in broiler chickens, and to evaluate its value as an alternative for antibiotics used as a feed additive. Two dosages of CS61 culture (0.1% and 1%) were fed to chickens for 28 days. The results showed that terminal body weight and daily weight gain in the treatment groups increased in a dose-dependent manner when compared with the control group. Dietary supplementation with CS61 culture also improved feed conversion rate compared to the control group. There were no treatment-related toxic effects in terms of clinical findings, mortality, necropsy findings, hematology, or serum biochemistry parameters in any group tested. The nitric oxide assay showed that CS61 peptide has a dose-dependent inhibitory effect on lipopolysaccharide-induced nitric oxide production in RAW 264.7 cells. The results of this experiment indicated that dietary supplementation of CS61 culture may improve growth performance and feed conversion efficiency in chickens through its anti-inflammatory effect.

• Journal of Life Science
• /
• v.23 no.2
• /
• pp.324-331
• /
• 2013

The addition and removal of N-acetylglucosamine (GlcNAc) molecules on serine or threonine residues of a protein is called O-GlcNAcylation. This post-translational modification occurs on both cytoplasmic and nuclear protein, and is fast and reversible as comparable to phosphorylation. In contrast to the phospho-signaling cycles, this emerging moon-lightening signaling is cycled by only two enzymes, O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA). The simple machinery is a good evolutionary adaptation of a cell for quick accommodation to continuously fluctuating intra- and extracellular microenvironments. Rather than "switching" on or off a specific proteins - this would be done by phosphorylation where numerous specific kinases and phosphatases are involved - O-GlcNAcylation would play a "rheostat" which would be much more delicately increase or decrease the efficacy of signal transductions in response to cellular nutrient and stress conditions. Interestingly, recent evidence indicates that O-GlcNAc is further modified by phosphorylation. The O-GlcNAc-P will upgrade the modulation efficiency of cellular processes to continuous 'analogue' level. So far, only one protein AP180 was reported to have O-GlcNAc-P on Thr310. But, proteomic data from our laboratory indicate that there are multiple O-GlcNAc-P proteins, constituting "O-GlcNAc-P'om". This will focus on the possibility of existence of "O-GlcNAc-P'om".

• Journal of Life Science
• /
• v.15 no.6 s.73
• /
• pp.1013-1021
• /
• 2005

The metagenomes of complex microbial communities are rich sources of novel biocatalysts. The gene encoding an extracellular $\alpha$-amylase from a genomic DNA of cow rumen was cloned in Escherichia coli DH5$\alpha$ and sequenced. The $\alpha$-amylase (amyA) gene was 1,893 bp in length, encoding a protein of 631 amino acid residues with calculated molecular weight of 70,734 Da. The molecular weight of the enzyme was estimated to be about 71,000 Da by active staining of a SDS-PACE. The enzyme was 21 to $59\%$ sequence identical with other amyloyltic enzymes. The AmyA was optimally active at pH 6.0 and $40\%$. The AmyA had a calculated pI of 5.87. AmyA expressed in E. coli DH5$\alpha$ was enhanced in the presence of $Mg^{2+}$ (20 mM) and $Ca^{2+}$ (30 mM) and inhibited in the presence of $Fe^{2+}$ and $Cu^{2+}$. The origin of amyA gene could not be confirmed by PCR using internal primer of amyA gene from extracted genomic DNA of 49 species rumen culturable bacteria so far. An amyh is supposed to obtained from unculturable rumen bacterium in cow rumen environment.

• Journal of Life Science
• /
• v.12 no.3
• /
• pp.264-273
• /
• 2002

We have isolated and artificially expressed three cDNA clones of Capsicum annuum PR5 genes for elucidating the antifungal activity against Phytophthora capsici which contracted a hot pepper root rot in field condition. Three divergent PR5 proteins from hot pepper were designated as CAPR5-1 and CAPR5-2 from susceptible cultivar (Subicho) as well as CAPR5-3 from resistant cultivar (CM331) in response to P. capsici. The cDNA similarity was found over 80% of identity among the three CAPR5s, and deduced amino acid sequence was characterized that all of CAPR5s contained 16 cysteine residues which possibly had a significant role in the structural formation. The result of genomic DNA blot showed that CAPR5-1 and CAPR5-2 existed as single copy in the Subicho genome. Three recombinant CPARs in E. coli were identified by SDS-PACE, and each expressed protein was treated on the PDA medium which contained cultured pathogens. Although three CAPR5 proteins did not affected the hyphal growth of Glomerella glycines and Colletotrichum fagenarium, CAPR5-1, CAPR5-2, and CAPR5-3 showed a specific antifungal activities against P. capsici.

• Korean Journal of Food Science and Technology
• /
• v.45 no.1
• /
• pp.133-136
• /
• 2013

The purpose of this study was to compare a conventional culture method and real-time PCR for the detection of Yersinia enterocolitica (Y. enterocolitica) in sausage and in vegetable salad. Food samples inoculated with Y. enterocolitica were enriched in peptone-sorbitol bile-broth, and swabs were then streaked onto cefsulodin-irgasan-novobiocin agar. Biochemical tests for suspected colonies were performed with an API 20E strip. In parallel, real-time PCR was performed, targeting the 16S rRNA gene using 1 mL of enrichment broth. In sausage, the number of positive samples detected by culture method (49 out of 60) was similar (p>0.05) with that of real-time PCR (50 out of 60). However, the number of positive samples of real-time PCR (26 out of 60) was significantly higher (p<0.05) than that of the conventional culture method (6 out of 60) in vegetable salad. Real-time PCR could be an effective screening tool for detecting Y. enterocolitica, particularly in food samples with high levels of background flora, such as a vegetable salad.

• Journal of Food Hygiene and Safety
• /
• v.21 no.4
• /
• pp.244-249
• /
• 2006

The residue depletion of amoxicillin was investigated in the olive flounder (Paralichthys olivaceus), rockfish (Sebastes schlegeli), and red sea bream (Pagrus major) after 7 days treatment with medicated feed at a dose of 400 mg/kg bw/day. Fishes were sampled for muscle on 1st, 2nd, 3rd, 4th, and 5th day after treatment. Amoxicillin concentrations were determined by high performance liquid chromatography with fluorescence detector. The recovery rates of amoxicillin in muscle samples ranged 84.3-101.3% and 75.0-91.5% for the concentration of 0.05 mg/kg and 0.1 mg/kg, respectively. Amoxicillin concentrations detected on 1st day after treatment were 0.137, 0.131, and 0.172 mg/kg in the muscle of olive flounder, rockfish, and red sea bream, respectively. After a withdrawal of 3 days, muscle concentrations were 0.012, 0.010, and 0.017 mg/kg in the olive flounder, rockfish, and red sea bream, respectively. Amoxicillin was not detectable in muscle samples on 4 days following withdrawal of the medicated feed. From results of the present study, a withdrawal period of amoxicillin is proposed on 4 days after 7 days treatment with medicated feed at a dose of 400 mg/kg bw/day to avoid the presence of excessive residues of the edible muscles of olive flounder, rockfish, and red sea bream.

• Journal of fish pathology
• /
• v.26 no.3
• /
• pp.149-161
• /
• 2013

Viral haemorrhagic septicaemia virus (VHSV), the causative agent of viral haemorrhagic septicaemia (VHS), is an epidemic virus of cultured olive flounder Paralichthys olivaceus in Korea. In the present study, the entire glycoprotein (G) gene including several hypervariable regions from 36 isolates of diverse geographic and host origin and 8 Korean VHSV isolates from cultured olive flounder were analyzed. Phylogenetic analysis indicated that most of Asian VHSV belong to the genotype IVa group, suggesting that they originated from a common ancestral virus. Comparative sequence analysis of the complete G protein from Korean VHSV isolates revealed 3 Korean strain-specific nucleotide residues (nucleotide number of G-region: A755, T834 and T1221). These results suggest that Korean VHSV originated from a common ancestor, but these regional specific nucleotide sequences suggest that genetic differences of VHSV are more related to geographic areas than to host fish species.

• Korean Journal of Food Science and Technology
• /
• v.10 no.3
• /
• pp.306-312
• /
• 1978

Residue levels of an organochlorine insecticide, BHC, were determined for brown rice samples produced in Korea by collection and field experiments to obtain the following results. 1) Residue levels of total BHC in 112 samples (an Indica type variety Tongil) produced in 1976 and collected from 9 provinces in proportion to the production level of rice ranged from 0.0010 to 0.0762 ppm, the average being 0.0061 ppm. 2) The residue levels in samples from Jeonbook, Kyongnam and Choongnam provinces were higher than the average for whole samples. BHC isomers were found in the order of ${\alpha}>{\gamma}>{\beta}>{\delta}$ isomers, and the detection frequency by range were 89.3% below 0.01 ppm, 9.8% for $0.01{\sim}0.05{\;}ppm$ and 0.9% for $0.05{\sim}0.10{\;}ppm$. 3) In field experiments according to conventional agronomical practices, the brown rice samples after spraying of BHC at the first generation time of rice stem borer (4 kg of 6% granular formulation/10 a paddy field) showed a little higher residue level than control samples, but not more than 0.035 ppm, whereas samples after spraying at the second generation time (3 kg/10 a) contained in the range of $0.04{\sim}0.19\;ppm$.