• Journal of Microbiology and Biotechnology
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• 제9권4호
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• pp.404-413
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• 1999

Methanopyrus kandleri is a hyperthermophilic methanogen that represents one of the most heat-resistant organisms: the maximum growth temperature of M. kandleri is $110^{\circ}C$. A random sequence analysis of the genomic DNA of M. kandleri has been performed to obtain genomic information. More than 200 unique sequence tags were obtained and compared with the sequences in the GenBank and PIR databases. About 30% of the analyzed tags showed strong sequence similarity to previously identified genes involved in various cellular processes such as biosynthesis, transport, methanogenesis, or metabolism. When statistics relating to the frequency of codons were examined, the sequenced open reading frames showed highly biased codon usage and a high content of charged amino acids. Among the identified genes, a homologue of the catalytic subunit of carbon monoxide dehydrogenase (CODH) that reduces $CO_2$ to CO was cloned and sequenced in order to examine its detailed gene structure. The cloned gene includes consensus promoters. The amino acid sequence of the cloned gene shows a strong homology with the CODH genes from methanogenic Archaea, especially in the presumed binding sites for Fe-S centers.

• 농업과학연구
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• 제41권4호
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• pp.441-453
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• 2014

Antibiotics in the diets for poultry were not only used for avoiding and (or) control bacterial infections but for promoting growth of the birds. However, there has been massive concerns of negative effects of antibiotics on human health such as development of antibiotics-resistance bacteria and (or) genes. Subsequently, some of countries (i.e., European Union member of country and South Korea) banned the use of antibiotics as growth promoters in the diets for livestock industries in 2006 and 2011, respectively. Thus, it has become important to develop feeding strategies and feed additives to control and reduce the occurrence of diseases in livestock without using in-feed antibiotics. In this review, therefore, it is attempted to gather information with respect to (1) understanding the digestive physiology and (2) knowledge pertaining to interaction linking feed additives and its physiological and metabolic responses in broiler chickens.

• Food Science and Biotechnology
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• 제17권5호
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• pp.990-995
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• 2008

A thermostable $\alpha$-L-arabinofuranosidases ($\alpha$-L-AFase) is an industrially important enzyme for recovery of L-arabinose from hemicellulose. The recombinant $\alpha$-L-AFase from Thermotoga maritima was expressed in Escherichia coli by using a constitutive pHCE or an inducible pRSET vectors. In batch fermentation, the constitutive expression system resulted in slightly faster growth rate (0.78 vs. 0.74/hr) but lower enzyme activity (2,553 vs. 3,723 units/L) than those of the induction system. When fed-batch fermentation was performed, biomass and enzyme activity reached the highest levels of 36 g/L and 9,152 units/L, respectively. The fed batch cultures performed superior results than batch culture in terms of biomass yield (4.62-5.42 folds) and enzyme synthesis (3.39-4.00 folds). In addition, the fed-batch induction strategy at high cell density resulted in the best productivity in cell growth as well as enzyme activity rather than the induction method at low cell density or the constitutive expression.

• Asian-Australasian Journal of Animal Sciences
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• 제33권3호
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• pp.373-381
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• 2020

There is a need for newer feed additives due to legal prohibition on inclusion of growth promoting antibiotics in livestock diets in several countries due to antimicrobial resistance. In this context, rare earth elements (REE) have gained attention among animal nutritionists as potential growth promoters. Currently, several studies have reported better weight gain, milk production, egg laying capacity and feed conversion efficiency among different breeds of farm animals following supplementation with REE, with however largely inconsistent results. Furthermore, REE supplementation has also shown to improve ruminal fibrolytic and proteolytic activities as well as flavor of meat with negligible residues in edible tissue, however the mechanism behind this action is still unclear. According to existing research, due to their poor absorption and similarity with calcium REE might exert their action locally on gut microbial populations within the gastrointestinal tract (GIT). Moreover, REE have also shown anti-inflammatory, anti-oxidative as well as immune stimulating effects. The present review aims to broaden the knowledge about use of REE as feed additives for livestock and sum up efficacy of REE supplementation on performance and health of animals by comparing the findings. Till date, researches with REE have shown properties that make them a promising, new and safe alternative feed additive but further exploration is recommended to optimize effects and clarify discrepancy of various results before practical proposals can be drafted.

• 한국축산식품학회지
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• 제35권1호
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• pp.121-129
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• 2015

${\beta}$-agonists are anabolic compounds that promote fat loss and muscle gain, and their administration to livestock may provide economic benefits by increasing growth rate and feed efficiency. For these reasons, ${\beta}$-agonists are also commonly added to livestock feed as growth promoters. This can introduce a significant risk of secondary human poisoning through intake of contaminated meat. A new method for the simultaneous determination of three ${\beta}$-agonists (clenbuterol, ractopamine, and zilpaterol) was developed in this study and applied to various meat samples. The limits of quantification, derived through a validation test following Codex guidelines, were $0.2{\mu}g/kg$ for clenbuterol and zilpaterol, and $0.4{\mu}g/kg$ for ractopamine. The average recoveries for clenbuterol, ractopamine, and zilpaterol ranged from 109.1% to 118.3%, 95.3% to 109.0%, and 94.1% to 120.0%, respectively. The recovery and coefficient of variation (CV) values fell within the acceptable range according to the Codex guidelines. This method reduced the analysis time without decreasing detection efficiency by modifying the pretreatment steps. This method could be utilized to manage the safety of imported meat products from countries where zilpaterol use is still permitted, thereby improving public health and preventing ${\beta}$-agonist poisoning due to secondary contamination.

• Mycobiology
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• 제43권3호
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• pp.184-194
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• 2015

A compressive description of tropical milky white mushroom (Calocybe indica P&C var. APK2) is provided in this review. This mushroom variety was first identified in the eastern Indian state of West Bengal and can be cultivated on a wide variety of substrates, at a high temperature range ($30{\sim}38^{\circ}C$). However, no commercial cultivation was made until 1998. Krishnamoorthy 1997 rediscovered the fungus from Tamil Nadu, India and standardized the commercial production techniques for the first time in the world. This edible mushroom has a long shelf life (5~7 days) compared to other commercially available counterparts. A comprehensive and critical review on physiological and nutritional requirements viz., pH, temperature, carbon to nitrogen ratio, best carbon source, best nitrogen source, growth period, growth promoters for mycelia biomass production; substrate preparation; spawn inoculation; different supplementation and casing requirements to increase the yield of mushrooms has been outlined. Innovative and inexpensive methods developed to commercially cultivate milky white mushrooms on different lignocellulosic biomass is also described in this review. The composition profiles of milky white mushroom, its mineral contents and non-enzymatic antioxidants are provided in comparison with button mushroom (Agaricus bisporus) and oyster mushroom (Pleurotus ostreatus). Antioxidant assay results using methanol extract of milky white mushroom has been provided along with the information about the compounds that are responsible for flavor profile both in fresh and dry mushrooms. Milky white mushroom extracts are known to have anti-hyperglycemic effect and anti-lipid peroxidation effect. The advantage of growing at elevated temperature creates newer avenues to explore milky white mushroom cultivation economically around the world, especially, in humid tropical and sub-tropical zones. Because of its incomparable productivity and shelf life to any other cultivated mushrooms in the world, milky white mushroom could play an important role in satisfying the growing market demands for edible mushrooms in the near future.

• The Korean Journal of Physiology and Pharmacology
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• 제26권5호
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• pp.347-355
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• 2022

Abdominal aortic aneurysm (AAA) is a life-threatening disorder worldwide. Fibroblast growth factor 21 (FGF21) was shown to display a high level in the plasma of patients with AAA; however, its detailed functions underlying AAA pathogenesis are unclear. An in vitro AAA model was established in human aortic vascular smooth muscle cells (HASMCs) by angiotensin II (Ang-II) stimulation. Cell counting kit-8, wound healing, and Transwell assays were utilized for measuring cell proliferation and migration. RT-qPCR was used for detecting mRNA expression of FGF21 and activating transcription factor 4 (ATF4). Western blotting was utilized for assessing protein levels of FGF21, ATF4, and markers for the contractile phenotype of HASMCs. ChIP and luciferase reporter assays were implemented for identifying the binding relation between AFT4 and FGF21 promoters. FGF21 and ATF4 were both upregulated in Ang-II-treated HASMCs. Knocking down FGF21 attenuated Ang-II-induced proliferation, migration, and phenotype switch of HASMCs. ATF4 activated FGF21 transcription by binding to its promoter. FGF21 overexpression reversed AFT4 silencing-mediated inhibition of cell proliferation, migration, and phenotype switch. ATF4 transcriptionally upregulates FGF21 to promote the proliferation, migration, and phenotype switch of Ang-II-treated HASMCs.

• 한국미생물·생명공학회지
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• 제29권4호
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• pp.206-211
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• 2001

Klyyveromyces marxianus exoinulinase를 Saccharomyces cerevisiae에서 구성적으로 과발현 생산하기 위해, 구성적 promoter인 GAPDH, ADH1, PGK 및 ENOI promoters 하류에 exoinulinase 유전자 (INUI)의 ORF를 in frame으로 연결한 각각의 plasmi에 YIGP, pADHI,-INU, pPGK-INU 및 pENO-INU 를 구축하였다. 이들 각 plasmid를함유한 형질전환주 4종을 포도당 농도 5% 배지에서 회분배양한 결과 균체증식은 promoter에 따라 큰 차이를 보이지 않았지만 exoinulinase 발현수준과 plasmid 안정성은 사용한 promoter 에 크게 좌우되었다. 즉 exoinulinase 발현수준은 GAPDH PGK ADH1 ENO1 promoter 각각 1.70, 1.67 1.29, 0.80 unit/ml 였으며 plasmid 안정성은 GAPDH promoter 계의 55%를 제외하고 모두 80%이상으로 높게 나타났다. 이상의 plasmid 안정성과 exoinulinae 발현수준을 고려하여 ADH1 및 PGK 발현계를 선정하여 유가배양하였다 Yeast extract와 포도당을 간헐적으로 공급한 유가배양 결과, 두 발현계에서 약 30 g-DCW/1의 균체농도를 얻었지만, ADHI promoter 계에서는 3.70 unit/ml 의 최대 exoinulinase 활성과 96%의 plasmid 안정성을 보여TRh 반면에 PGK promoter 계는 각각 2.70 unit/ml/와 80%를 나타내었다. 따라서 plasmid 안정성과 긴 배양시간을 고려할 때 비선택적 영양배지를 사용하는 고농도세포 유가배양에서 ADH1 promoter가 exoinulinase 의 구성적 과발현, 생산에 더 적합할 것으로 사료된다.

• Asian-Australasian Journal of Animal Sciences
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• 제27권1호
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• pp.93-100
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• 2014

The banning of the use of antibiotics as feed additive has accelerated investigations of alternative feed additives in animal production. This experiment investigated the effect of pure citric acid or acidifier blend supplementation as substitute for antibiotic growth promoters on growth performance, fecal microbial count, and humoral immunity in weaned piglets challenged with Salmonella enterica serover Typhimurium and Escherichia coli KCTC 2571. A total of 60 newly weaned piglets (crossbred, 28-d-old; average 8 kg initial weight) were randomly assigned to four dietary treatments in a completely randomized design. Dietary treatments included NC (negative control; basal diet), PC (positive control; basal diet+0.002% apramycin), T1 (basal diet+0.5% pure citric acid), and T2 (basal diet+0.4% acidifier blend). All piglets were orally challenged with 5 mL of culture fluid containing $2.3{\times}10^8$ cfu/mL of E. coli KCTC 2571 and $5.9{\times}10^8$ cfu/mL of S. typhimurium at the beginning of the experiment. The PC group showed the highest ADG and ADFI, whereas gain:feed was improved in the PC and T1 group (p<0.05). All dietary treatments showed significant reduction in fecal counts of Salmonella and E. coli, compared to NC (p<0.05), with PC being better than T1 and T2. Significant elevation in fecal Lactobacillus spp. counts was shown by treatments with T1, T2, and PC, whereas Bacillus spp. counts were increased by treatment with T1 and T2 compared to NC and PC diet (p<0.05). Serum IgG concentration was increased by T1 diet (p<0.05), whereas IgM and IgA were not significantly affected by any of the dietary treatments (p>0.05). From these above results, it can be concluded that, as alternatives to antibiotics dietary acidification with pure citric acid or acidifiers blend did not fully ameliorate the negative effects of microbial challenges in respect of growth performance and microbial environment, however improved immunity suggested further research with different dose levels.

• Asian-Australasian Journal of Animal Sciences
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• 제21권2호
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• pp.252-261
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• 2008

Two experiments were conducted to compare the effects of feeding organic acids and antibiotic growth promoters in weaned pigs. In Exp. 1, 96 nursery pigs (Large White$\times$Landrace; initial weight $7.80{\pm}0.07kg$) were randomly allotted into one of four dietary treatments. Pigs in treatment 1 were fed a complex starter diet. Treatments 2 to 4 were the same as treatment 1 but supplemented with antibiotics (200 ppm chlortetracycline plus 60 ppm Lincospectin), 0.5% potassium diformate or 0.5% dry organic acid blend ACTIVATE Starter DA (ASD). During the 4-week post-weaning period, pigs fed ASD or antibiotics had better gain (p = 0.03) and feed efficiency (p = 0.04) than pigs fed the control diet. On d 14 post-weaning, pigs fed the control diet had the lowest fecal lactobacilli count among all dietary treatments (p = 0.02), whereas pigs fed ASD or antibiotics had a trend for lower fecal E. coli count compared to the control pigs (p = 0.08). Serum insulin-like growth factor-1 (IGF-1) of pigs fed ASD did not differ from pigs fed the control diet (p>0.05) at d 14 after weaning. In Exp. 2, 24 weaned pigs (Large White$\times$Long White; initial weight $5.94{\pm}0.33kg$) were allotted into four groups and housed individually. Pigs were fed a control diet or diets supplemented with antibiotics (100 ppm colistin sulfate, 50 ppm Kitasamycin plus 60 ppm Olaquindox), 0.5% or 1% ASD. All pigs were orally challenged with E. coli $K88^+$ on d 5. During d 5 to 14 after challenge, pigs fed antibiotics, 0.5% or 1% ASD had better gain (p = 0.01) and feed efficiency (p = 0.03) than pigs fed the control diet. On d 14, compared to the control pigs, pigs fed 0.5% ASD had higher lactobacilli in the duodenum and pigs fed 1% ASD and antibiotics had a trend for higher lactobacilli in the ileum (p = 0.08). Pigs fed antibiotics, 0.5% or 1% ASD diets tended to have decreased ileal E. coli count compared to those fed the control diet (p = 0.08). Serum interleukin-6 and cortisol and digesta pH values were not affected by treatment or time. These results indicate that feeding ASD can improve the growth performance of weaning pigs, mainly via modulating intestinal microflora populations without affecting gastrointestinal pH or immune indices.