• Korean Journal of Microbiology
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• v.25 no.1
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• pp.52-56
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• 1987

The evidences that Lam B protein of E. coli is used as a receptor for infections of bacteriophage N4 as well as bacteriophage lambda were obtained from the following experimental results. First, all of the isolated lambda resistant dlones possessing foreign DNA fragments in the plasmids were also resistant to bacteriophage N4, but not to bacteriophage $\phi$ 80, T4 and T7. Second, when the plasmid DNA was treated with various restriction enzymes and ligated to delete the total or a portion of the foreign DNA fragments, the deleted plasmids lost the resistant activities to lambda and N4, simultaneously. Third, after amplification of Lam B protein about 200 times by inducing the protein using maltose as a sole carbon source, the host E. coli became sensitive to both lambda and N4.

• Molecules and Cells
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• v.42 no.4
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• pp.285-291
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• 2019

Eukaryotic cells use conserved quality control mechanisms to repair or degrade defective proteins, which are synthesized at a high rate during proteotoxic stress. Quality control mechanisms include molecular chaperones, the ubiquitin-proteasome system, and autophagic machinery. Recent research reveals that during autophagy, membrane-bound organelles are selectively sequestered and degraded. Selective autophagy is also critical for the clearance of excess or damaged protein complexes (e.g., proteasomes and ribosomes) and membrane-less compartments (e.g., protein aggregates and ribonucleoprotein granules). As sessile organisms, plants rely on quality control mechanisms for their adaptation to fluctuating environments. In this mini-review, we highlight recent work elucidating the roles of selective autophagy in the quality control of proteins and RNA in plant cells. Emphasis will be placed on selective degradation of membrane-less compartments and protein complexes in the cytoplasm. We also propose possible mechanisms by which defective proteins are selectively recognized by autophagic machinery.

• Korean Journal of Animal Reproduction
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• v.27 no.2
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• pp.143-152
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• 2003

The objective of this study were to investigate the effects of Se and Vit. E administration on blood chemical values and Vit. E concentrations of serum in calves born from Hanwoo dams injected Se and Vit. E at late pregnancying periods. The effects of Se and Vit. E administration of blood chemical values in calves born from Hanwoo dams injected Se and Vit. E at the last month of pregnancying periods were examined. In albumin concentration of blood, the Vit. E 2000IU group were slightly higher than other groups and the cholesterol concentrations were also higher in Vit. E 15001u group than other groups. But, another components examined of blood chemical values were not significantly different in all experimental groups. The blood chemical values in calves born from Hanwoo dams administrated Se and Vit. E at two months before parturition were examined. However, there were not significantly different in all experimental groups in concentrations of albumin, cholesterol, BUN, creatinine, glucose, inorganic phosphorous, calcium, total protein and triglycerides. The concentrations of serum Vit. E in calves born from Hanwoo dams administrated Se and Vit. E at 30 and 15 days before parturition were examined. The concentrations of Vit. E in serum were higher in treatment groups than in control group(P>0.05). The concentrations of serum Vit. E in calves born from Hanwoo dams administrated Se and Vit. E at 60 days before parturition were examined, the concentrations of Vit. E in serum were slightly higher in groups administrated than in control group(P>0.05), but there were not significantly difference in all experimental groups.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.5
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• pp.650-654
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• 2011

An experiment involving 180 straight run one-day-Cobb broilers was conducted to evaluate the effect of supplementation of L-leucine with different levels of crude protein (CP) on carcass composition and sensory characteristics of broiler grower-finisher chickens. Six experimental diets comprising two levels of crude protein (CP) i.e., 20 and 20% with three levels of L-leucine i.e. 0, 0.5 and 0.67%, were offered to birds from 21-42 d of age. The birds were randomly divided into 36 experimental pens, 5 chickens in each pen, and there were 6 replicates under each diet. L-leucine supplementation did not affect the bone and lean, whereas fat was decreased (p<0.05) when L-leucine was added at 0.5%. Similarly, there were no significant differences (p>0.05) in the lean, fat and bone among chickens fed two levels of CP. No significant differences between dietary treatments were observed on any sensory characteristics affected by dietary L-leucine and CP. From this study, it is obvious that supplementation of up to 0.5% L-leucine reduced fat. However, other characteristics were not affected by supplementation of L-leucine. Similarly, reduction of body composition and sensory characteristics were not apparent on a diet low in CP.

• Journal of Microbiology and Biotechnology
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• v.8 no.1
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• pp.34-41
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• 1998

A method was developed for the controlled expression of an antimicrobial peptide magainin in Escherichia coli. A series of concatemeric magainin genes was constructed with a gene amplification vector, and fused to the 3'end of malE gene encoding the affinity ligand, E. coli maltose-binding protein (MBP). The construct directed the synthesis of the fusion protein with the magainin polypeptide fused to the C-terminus of MBP. The fusion protein was expressed in a tightly regulatable expression system which was under the control of an invertible promoter. The MBP-fused magainin monomer was expressed efficiently. However, the expression level of the MBP-fused magainin in E. coli decreased with the increasing size of multimers possibly because of the transcription and translation inhibition by the multimeric peptides. After purification using an amylose affinity column, the fusion protein was digested by factor Xa at a specific cleavage site between the monomers. The recombinant magainin had an antimicrobial activity identical to that of synthetic magainin. This experiment shows that a biologically active, antimicrobial peptide magainin can be produced by fusing to MBP, along with a promoter inversion vector system.

• Journal of Microbiology and Biotechnology
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• v.23 no.11
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• pp.1529-1535
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• 2013

Tuberculosis is a worldwide epidemic disease caused by Mycobacterium tuberculosis, with an estimated one-third of the human population currently affected. Treatment of this disease with aminoglycoside antibiotics has become less effective owing to antibiotic resistance. Recent determination of the crystal structure of the M. tuberculosis Rv3168 protein suggests a structure similar to that of Enterococcus faecalis APH(3')-IIIa, and that this protein may be an aminoglycoside phosphotransferase. To determine whether Rv3168 confers antibiotic resistance against kanamycin, we performed dose-response antibiotic resistance experiments using kanamycin. Expression of the Rv3168 protein in Escherichia coli conferred antibiotic resistance against $100{\mu}M$ kanamycin, a concentration that effected cell growth arrest in the parental E. coli strain and an E. coli strain expressing the $Rv3168^{D249A}$ mutant, in which the catalytic Asp249 residue was mutated to alanine. Furthermore, we detected phosphotransferase activity of Rv3168 against kanamycin as a substrate. Moreover, docking simulation of kanamycin into the Rv3168 structure suggests that kanamycin fits well into the substrate binding pocket of the protein, and that the phosphorylation-hydroxyl-group of kanamycin was located at a position similar to that in E. faecalis APH(3')-IIIa. On the basis of these results, we suggest that the Rv3168 mediates kanamycin resistance in M. tuberculosis, likely through phosphotransferase targeting of kanamycin.

• Food Science and Biotechnology
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• v.18 no.2
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• pp.396-401
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• 2009

The nucleotide sequence contains 2 open reading frames encoding a 45-amino-acid protein homologous to a transcriptional repressor protein CopG, and a 203-amino-acid protein homologous to a replication protein RepB. Putative countertranscribed RNA, a double-strand origin, and a single-strand origin were also identified. A shuttle vector, pUCL2.1, for various lactic acid bacteria (LAB) was constructed on the basis of the pCL2.1 replicon, into which an erythromycin-resistance gene as a marker and Escherichia coli ColE1 replication origin were inserted. pUCL2.1 was introduced into E. coli, Lc. lactis, Lactobacillus (Lb.) plantarum, Lb. paraplantarum, and Leuconostoc mesenteroides. The recombinant LAB maintained traits of transformed plasmid in the absence of selection pressure over 40 generations. Therefore, pUCL2.1 could be used as an E. coli/LAB shuttle vector, which is an essential to engineer recombinant LAB strains that are useful for food fermentations.

• Preventive Nutrition and Food Science
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• v.20 no.3
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• pp.176-182
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• 2015

Abalone protein was hydrolyzed by enzymatic hydrolysis and the optimal enzyme/substrate (E/S) ratios were determined. Abalone protein hydrolysates (APH) produced by Protamex at E/S ratio of 1:100 showed angiotensin I converting enzyme inhibitory activity with $IC_{50}$ of 0.46 mg/mL, and APH obtained by Flavourzyme at E/S ratio of 1:100 possessed the oxygen radical absorbance capacity value of $457.6{\mu}M$ trolox equivalent/mg sample. Flavourzyme abalone protein hydrolysates (FAPH) also exhibited $H_2O_2$ scavenging activity with $IC_{50}$ of 0.48 mg/mL and $Fe^{2+}$+ chelating activity with $IC_{50}$ of 2.26 mg/mL as well as high reducing power. FAPH significantly (P<0.05) protected $H_2O_2$-induced hepatic cell damage in cultured hepatocytes, and the cell viability was restored to 90.27% in the presence of FAPH. FAPH exhibited 46.20% intracellular ROS scavenging activity and 57.89% lipid peroxidation inhibition activity in cultured hepatocytes. Overall, APH may be useful as an ingredient for functional foods.

• BMB Reports
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• v.52 no.2
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• pp.119-126
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• 2019

The tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) initiates the extrinsic apoptotic pathway through formation of the death-inducing signaling complex (DISC), followed by activation of effector caspases. TRAIL receptors are composed of death receptors (DR4 and DR5), decoy receptors (DcR1 and DcR2), and osteoprotegerin. Among them, only DRs activate apoptotic signaling by TRAIL. Since the levels of DR expressions are higher in cancer cells than in normal cells, TRAIL selectively activates apoptotic signaling pathway in cancer cells. However, multiple mechanisms, including down-regulation of DR expression and pro-apoptotic proteins, and up-regulation of anti-apoptotic proteins, make cancer cells TRAIL-resistant. Therefore, many researchers have investigated strategies to overcome TRAIL resistance. In this review, we focus on protein regulation in relation to extrinsic apoptotic signaling pathways via ubiquitination. The ubiquitin proteasome system (UPS) is an important process in control of protein degradation and stabilization, and regulates proliferation and apoptosis in cancer cells. The level of ubiquitination of proteins is determined by the balance of E3 ubiquitin ligases and deubiquitinases (DUBs), which determine protein stability. Regulation of the UPS may be an attractive target for enhancement of TRAIL-induced apoptosis. Our review provides insight to increasing sensitivity to TRAIL-mediated apoptosis through control of post-translational protein expression.

• Journal of Applied Biological Chemistry
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• v.66
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• pp.128-137
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• 2023

Transcriptome analysis revealed that the sinR gene encoding a transition-state regulator of Bacillus pumilus, genetically close to B. subtilis, was expressed at high levels during growth. The sinR gene is the second gene of the sinIR operon consisting of three promoters and two structural genes in B. subtilis. This study used the sinIR promoter of B. subtilis DB104 to construct a recombinant protein expression system. First, the expression ability depending on the number of sinIR promoter was investigated using enhanced green fluorescent protein (eGFP). The expression level of eGFP was slightly higher when using two promoters (Psin2) than using original promoters. The Psin2 promoter was further engineered by modifying the repressor binding site and -35 and -10 regions. Shine-Dalgarno (SD) sequence of the sinI gene was modified to the consensus sequence. Finally, combining the engineered Psin2 promoter with the modified SD sequence increased the expression level of eGFP by about 13.4-fold over the original promoter. Our results suggest that the optimized sinIR promoter could be used as a novel tool for recombinant protein expression in B. subtilis.