• Tuberculosis and Respiratory Diseases
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• v.45 no.2
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• pp.369-379
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• 1998

Background: Platelet-activating factor(PAF) might play an important role in the development of acute respiratory distress syndrome. Since PAF induced lung injury is similar to changes of acute respiratory distress gyndrome, and abnormalities in surfactant function have been described in acute respiratory distress syndrome, the authors investigated the effects of PAF on the regulation of surfactant protein A, B and C mRNA accumulation Method: The effects of PAF on gene expression of surfactant protein A, B and C in 24 hours after intratracheal injection of PAF in rats. Surfactant protein A, B and C mRNAs were measured by filter hybridization. Results: The accumulation of SP-A mRNA in PAF treated group was significantly decreased by 37.1 % and 41.6%, respectively compared to the control group and the group treated with Lyso-PAF(p<0.025, p<0.01). The accumulation of SP-B mRNA in PAF treated group was decreased by 18.7% and 32.2 %, respectively compared to the control group and the group treated with Lyso-PAF but statistically not significant. The accumulation of SP-C mRNA in PAF treated group was significantly decreased by 30.7% and 38.5%, respectively compared to the control group and the group treated with Lyso-PAF(p<0.l, p<0.01). Conclusion: These findings represent a marked inhibitory effects of platelet-activating factor on surfactant proteins expression in vivo. This supports, in turn, 'platelet-activating factor might be related to pathogenesis of acute respiratory distress syndrome.

• KSBB Journal
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• v.13 no.2
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• pp.133-140
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• 1998

Using rlFN-$\alpha$ and rhGH as the model proteins, the refolding performances of the published processes were evaluated and compared. Key engineering parameters such as the type of denaturant and this concentration, protein concentration in the refolding buffer, and pH and ionic strength of the buffer were experimentally investigated. Furthermore, the role of a co-solvent of surfactant type in aggregation reduction was also studied. Of the denaturants tested (8M urea, 6M guanidine HCI, 0.5% SDS), SDS at alkaline pH (9.5) and ambient temperature gave the highest recovery yield. The SDS process was effective in the refolding of observed where dissolution proceeded better under lower strength (10 mM) but aggregation was suppressed under higher strength (>50 mM.) When PEG-4000 and/or Tween were added as co-solvent or refolding-enhancing additive, 1.6-2 times higher yield was realized. The‘masking’of the hyrophobic patches located on the surface of the protein with the surfactant molecules was believed to be responsible for the considerable reduction in aggregation during refolding.

• Microbiology and Biotechnology Letters
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• v.18 no.5
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• pp.517-524
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• 1990

The solubilization and desolubilization of proteins in CTAB/hexanol/isooctane reverse micellar system were investigated for the selective separation of proteins. Several proteins were used, including bovine serum albumin (BSA), pepsin, trysin and ribonuclease-a. Most proteins could be solubilized into reverse micelles in the pH range above the isoelectric point of each protein, where the net charge of protein was opposite to that of surfactant. However BSA was solubilized above pH 10, which is serveral pH units above the pI 4.9. The kinds of anions in aqueous phase influenced on protein solubilization while no significant trend was observed with different cations, Protein solubilization decreased with increase of the ion size in the order of F -, C1-, Br- and I -. The size of CTAB micelles did not change significantly with increasing ionic strength, but the solubilization decreased. Protein desolubilization showedropposite behaviors to the solubilization. Several model mixtures such as pepsin/ trypsin, pepsin/ribonuclease-a and BSAlribonucleaee-a were successfully separated from each other without changing enzymatic activities.

• Food Science of Animal Resources
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• v.24 no.1
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• pp.80-85
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• 2004

This study was carried out to separate immunoglobulin G(IgG) from colostrum using reverse micellar extraction of cationic surfactant and to suggest suitable extraction conditions. The reconstituted colostrum powder was solubilized into a reverse micellar phase containing CDAB(cetyldimethylethyl ammonium bromide) by mixing equal volume of the aqueous and organic phase with constant stirring. The solubilization of proteins from the aqueous to the organic phase was manipulated by pH and ionic strength of the aqueous phase and concentration of surfactant in the organic phase. Based on the SDS-PAGE and densitometry, about more than 90% of initial IgG was remained in the aqueous phase after reverse micellar extraction. Although the aqueous phase contained lactoferrin and bovine serum albumin as minor components, about 93% of the total protein was IgG. The efficient extraction was achieved by the reaction of sodium phosphate buffer(pH 8) containing 50 mM KCl and organic phase containing 100 mM CDAB. The separation of IgG using reverse micellar extraction was simple, highly efficient and easy to be scaled up.

• Journal of Environmental Health Sciences
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• v.43 no.4
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• pp.273-279
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• 2017

Objectives: Carbon nanotubes (CNTs) are next-generation industrial nanoparticles which possess excellent mechanical strength along with good thermal conductivity and electric properties. Given these characteristics, carbon nanotubes are being widely applied in various fields, including research and development. However, concerns have been raised over hazardous properties due to their similar fiber shape to asbestos. Recent studies have shown that CNTs pose potential hazards which may cause fibrosis and/or lung inflammation similarly to asbestos. Methods: After intratracheal instillation of SWCNTs and MWCNTs to rats, pulmonary surfactant (PS) of the SWCNTs and MWCNTs was measured and analyzed using bronchoalveolar lavage fluid collected from the lung. After a single intratracheal instillation of SWCNTs and MWCNTs, phospholipid predominantly showed a significant increase compared to the control group, while proteins exhibited a significant increase both three days and one week after instillation. Results: As a result of surface tension, MWCNTs showed a significant decrease three days after treatment compared to the control group. In the case of the total cell number three days after instillation, MWCNTs revealed a temporarily significant increase when compared to the control group. For PMN number, when compared to the control group, SWCNTs displayed a significant increase throughout the observation period, while MWCNTs showed a significant increase three days and three months after treatment. Conclusions: After exposure to CNTs, the total cell number and PNT number, which indicate inflammatory response, were significantly increased. Therefore, this study suggests fiber-shaped CNTs may have a harmful effect on the lungs.

• Clinical and Experimental Pediatrics
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• v.49 no.4
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• pp.455-459
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• 2006

The major pathogenesis of acute respiratory distress syndrome (ARDS) is an inflammatory process that results from a diversity of injuries to the body. Due to the various cytokines and vasoactive peptides released from the endothelium, the vascular permeability is increased; the migration of inflammatory cells and the leakage of plasma proteins then occur and edema develops in the alveolus. There is a hypothesis that the impairment of alveolar recruitment in ARDS is caused by a defect of the surfactant system and the resultant increase of alveolar surface tension. This has been studied in pediatric patients in ARDS; after the administration of surfactant, hypoxia, respiratory symptoms and survival chances were improved. To alleviate the major pathogenic mechanism in this disease, that is to say, inflammation of the lung, steroids have been used and studied as another treatment modality for ARDS, and it has been concluded that the administration of low dose methylprednisolone may improve patients' symptoms and survival rates. We report here on a case of a young infant admitted with ARDS, who, after the intratracheal administration of 120 mg/kg surfactant, on $PaO_2/FiO_2$ was elevated. Subsequent low doses of methylprednisolone were given, and the symptoms did not recur, and no fibrotic change was shown during the follow-up period of 2 months.

• Tuberculosis and Respiratory Diseases
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• v.54 no.4
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• pp.439-448
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• 2003

Background : Surfactant protein B(SP-B) and surfactant protein C(SP-C) are important in accelerating surface spreading of surfactant phospholipid. The glucocorticoids accelerate the morphologic differentiation of epithelial cells into type II cells and increase the rate of phosphatidylcholine synthesis. The hydrophobic surfactant protein has been shown to be upregulated by glucocorticoids in vitro, however, its regulation in vivo is not well established. Methods : The authors investigated the effects of glucocorticoid on the accumulation of mRNA encoding SP-B and SP-C protein content of the lung. Adult rats were given different doses of subcutaneous dexamethasone and sacrificed at 24 hours and 1 week. SP-B and SP-C mRNA were measured by a filter hybridization method. Results : 1) The accumulation of SP-B mRNA at 24 hours after 0.2 mg/kg dexamethasone treatment was increased by 23.7%. 2) The accumulation of SP-B mRNA at 1 week after 2 mg/kg dexamethasone treatment was significantly increased by 96.6%(P<0.001). 3) The accumulation of SP-C mRNA at 24 hours after 0.2 mg/kg dexamethasone treatment was significantly increased by 42.7%(P<0.01). 4) The accumulation of SP-C mRNA at 1 week after 2 mg/kg dexamethasone treatment was significantly increased by 60.0% (P<0.01). Conclusion : The authors concluded that dexamethasone treatment in vivo resulted in increased levels of SP-B mRNA and SP-C mRNA. These results suggested that dexamethasone stimulates the synthesis of hydrophobic proteins associated with surfactant.

• KSBB Journal
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• v.14 no.6
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• pp.661-664
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• 1999

Proteins were extracted from an aqueous phase with reversed micelles. The effect of pH, and salt concentration on the solubilization of lysozyme in AOT/isooctane solution was studied to explore the potential for employing this solvent system in the large-scale recovery and concentration of proteins using liquid extraction. For pH values below the isoelectric point, pl of the protein, solubilization was high, probably owing to strong electrostatic interactions between the positively charged proteins and the anionic surfactant heads forming the inner micelle wall. At low ionic strength complete solubilization of the protein was observed. A pH higher than the pl of lysozyme and a salt concentration lower than that of the water pool were required for the recovery aqueous phase to ensure the back extraction of lysozyme from the AOT reversed micelles.

• KSBB Journal
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• v.5 no.3
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• pp.215-221
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• 1990

The solubilization of BSA, pepsin, trypsin and ribonuclease-a in cationic reverse micellar solutions has been investigated. For complete solubilization into reverse micellar solutions, pH values of several pH units above the isoelectric point of each protein were required. Solubilization was observed to decrease with increasing ionic strength of KCI. The size of empty micelles showed no significant change with increasing ionic strength. Trioctylmethyl ammonium chloride (TOMAC) in cyolohexane showed the lowest solubilization for the proteins. The system didodecyl dimethyl ammonium bromide (DDAB)-tetrachloroethylene was capable of solubilizing larger amounts of proteins than the system DDAB-benzene. Cetyl trimethyl ammonium bromide(CTAB)-hexanol-isooctane system showed lower solubilization than DDAB-tetrachloroethylene system, while it had higher Wo value.

• Biotechnology and Bioprocess Engineering:BBE
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• v.11 no.1
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• pp.32-37
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• 2006

In this study, we have purified and characterized the membrane bound nitrate reductase obtained from the denitrifying bacteria, Ochrobactrum anthropi SY509, which was isolated from soil samples. O. anthropi SY509 can grow in minimal medium using nitrate as a nitrogen source. We achieved an overall purification rate of 15-fold from the protein extracted from the membrane fraction, with a recovery of approximately 12% of activity. The enzyme exhibited its highest level of activity at pH 5.5, and the activity was increased up to $70^{\circ}C$. Periplasmic and cytochromic proteins, including nitrite and nitrous oxide reductase, were excluded during centrifugation and were verified using enzyme essay. Reduced methyl viologen was determined to be the most efficient electron donor among a variety of anionic and cationic dyestuffs, which could be also used as an electron donor with dimethyl dithionite. The effects of purification and storage conditions on the stability of enzyme were also investigated. The activity of the membranebound nitrate reductase was stably maintained for over 2 weeks in solution. To maintain the stability of enzyme, the cell was disrupted using sonication at low temperatures, and enzyme was extracted by hot water without any surfactant. The purified enzyme was stored in solution with no salt to prevent any significant losses in activity levels.