• Journal of Microbiology and Biotechnology
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• v.24 no.6
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• pp.803-811
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• 2014

Concerns over drug-resistant bacteria have stimulated interest in developing alternative methods to control bacterial infections. Endolysin, a phage-encoded enzyme that breaks down bacterial peptidoglycan at the terminal stage of the phage reproduction cycle, is reported to be effective for the control of bacterial pathogenic bacteria. Bioinformatic analysis of the SPN9CC bacteriophage genome revealed a gene that encodes an endolysin with a domain structure similar to those of the endolysins produced by the P1 and P22 coliphages. The SPN9CC endolysin was purified with a C-terminal oligo-histidine tag. The endolysin was relatively stable and active over a broad temperature range (from $24^{\circ}C$ to $65^{\circ}C$). It showed maximal activity at $50^{\circ}C$, and its optimum pH range was from pH 7.5 to 8.5. The SPN9CC endolysin showed antimicrobial activity against only gram-negative bacteria and functioned by cutting the glycosidic bond of peptidoglycan. Interestingly, the SPN9CC endolysin could lyse intact gram-negative bacteria in the absence of EDTA as an outer membrane permeabilizer. The exogenous lytic activity of the SPN9CC endolysin makes it a potential therapeutic agent against gram-negative bacteria.

• The Korean Journal of Physiology and Pharmacology
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• v.14 no.3
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• pp.127-132
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• 2010

Reactive oxygen species (ROS), which include hydrogen peroxide ($H_2O_2$), the superoxide anion (${O_2}^-{\cdot}$), and the hydroxyl radical ($OH{\cdot}$), are generated as by-products of oxidative metabolism in cells. The cerebral cortex has been found to be particularly vulnerable to production of ROS associated with conditions such as ischemia-reperfusion, Parkinson's disease, and aging. To investigate the effect of ROS on inhibitory GABAergic synaptic transmission, we examined the electrophysiological mechanisms of the modulatory effect of $H_2O_2$ on GABAergic miniature inhibitory postsynaptic current (mIPSCs) in mechanically isolated rat cerebral cortical neurons retaining intact synaptic boutons. The membrane potential was voltage-clamped at -60 mV and mIPSCs were recorded and analyzed. Superfusion of 1-mM $H_2O_2$ gradually potentiated mIPSCs. This potentiating effect of $H_2O_2$ was blocked by the pretreatment with either 10,000-unit/mL catalase or $300-{\mu}M$ N-acetyl-cysteine. The potentiating effect of $H_2O_2$ was occluded by an adenylate cyclase activator, forskolin, and was blocked by a protein kinase A inhibitor, N -(2-[p-bromocinnamylamino] ethyl)-5-isoquinolinesulfonamide hydrochloride. This study indicates that oxidative stress may potentiate presynaptic GABA release through the mechanism of cAMP-dependent protein kinase A (PKA)-dependent pathways, which may result in the inhibition of the cerebral cortex neuronal activity.

• The Korean Journal of Physiology and Pharmacology
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• v.22 no.6
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• pp.697-703
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• 2018

Myoblast fusion depends on mitochondrial integrity and intracellular $Ca^{2+}$ signaling regulated by various ion channels. In this study, we investigated the ionic currents associated with $[Ca^{2+}]_i$ regulation in normal and mitochondrial DNA-depleted(${\rho}0$) L6 myoblasts. The ${\rho}0$ myoblasts showed impaired myotube formation. The inwardly rectifying $K^+$ current ($I_{Kir}$) was largely decreased with reduced expression of KIR2.1, whereas the voltage-operated $Ca^{2+}$ channel and $Ca^{2+}$-activated $K^+$ channel currents were intact. Sustained inhibition of mitochondrial electron transport by antimycin A treatment (24 h) also decreased the $I_{Kir}$. The ${\rho}0$ myoblasts showed depolarized resting membrane potential and higher basal $[Ca^{2+}]_i$. Our results demonstrated the specific downregulation of $I_{Kir}$ by dysfunctional mitochondria. The resultant depolarization and altered $Ca^{2+}$ signaling might be associated with impaired myoblast fusion in ${\rho}0$ myoblasts.

• Childhood Kidney Diseases
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• v.17 no.1
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• pp.13-18
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• 2013

Podocytopathy is glomerular lesions characterized by podocyte injury. It is observed in various glomerular diseases, but minimal change disease and focal segmental glomerulosclerosis (FSGS) are the prototypes. In this review, morphologic features of podocyte injury and subtypes of FSGS will be reviewed briefly. Effacement of podocyte foot processes is the most common feature of podocyte injury. As podocytic injury progresses, intracytoplasmic vacuoles, subpodocytic cyst, detachment of podocytes from the glomerular basement membrane and apoptosis develop. Glomerular capillary loops in epithelium-denuded area undergo capillary collapse. Synechia and hyalinosis may accompany this lesion. To manifest segmental sclerosis, podocyte loss above a threshold level may be required. Injured podocytes can injure neighboring intact podocytes, and thereby spread injury within the same lobule. FSGS can be categorized into five subtypes by morphologic characteristics; not otherwise specified (NOS), perihilar, cellular, tip, and collapsing types. Each subtype has been reported to show different clinical courses and associated conditions, but there are controversies on its significance. With recent progress in the discovery of genetic abnormalities causing FSGS and plasma permeability factors, we expect to unravel pathophysiology of FSGS and to understand histological sequences leading to FSGS in near future.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.2
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• pp.167-175
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• 2000

This paper describes the magnetic orientation of bull sperm separated into the head and the flagellum treated by DTT or heparin in a 5,400G static field. Semen samples collected from four bulls (Japanese Black) were mixed to the same sperm density. One percentage triton X-100 was used to extract the plasma membrane. The intact and demembranated sperm suspensions were treated with 20, 200, 2,000 mM DTT, 100, 1,000 or 10,000 units heparin solutions at $4^{\circ}C$ for 6 days. The decondensation of the sperm nuclei treated by DTT or heparin was examined by measuring the head area at 1, 3 and 6 days. After measuring the area, each sample was exposed to a 5,400G static magnetic field generated by Nd-Fe-B permanent magnets for 24 hours at room temperature. Results showed that the sperms were separated into the head and the flagellum through the DTT treatment. Almost of the separated heads showed that their long axis oriented perpendicularly to the magnetic lines of force, and most of the long axis perpendicularly oriented heads showed that their flat plane oriented perpendicularly in a 5,400G magnetic field. Also, the demembranation of the head tended to increase those perpendicular orientations, while those perpendicular orientations of the head declined with the decondensation of the sperm nuclei. These findings suggest that strong magnetic anisotropy for the perpendicular orientation of the long axis and the flat plane of the head occurs in the sperm nuclei in a 5,400G magnetic field. The separated flagellum showed lower parallel orientation, and the separated and demembranated flagellum showed parallel orientation to the magnetic lines of force in this magnetic field. These findings suggest that weak magnetic anisotropy of the parallel orientation of the flagellum occurs in the inside components in a 5,400G field.

• Journal of Plant Biology
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• v.35 no.2
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• pp.143-153
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• 1992

Nectar secretion from extrafloral nectary cells of Prunus yedoensis was examined by light and electron microscopy. Nectaries were composed of two or three layers of secretory cells and one layer of subsectretory cells. Vascular bundles in the petioles were connected to those of the subsectretory cell layer. Secretory cells had a number of mitochondria with poorly developed cristae. Plastids had little thylakoids and small vesicles, about 0.2 to 0.3 mm in diameter; however, no plastids had starch grains. Calcium oxalate crystals and plasmodesmata were frequently observed in the subsectretory and secretory cells, respectively. And nectar substances were observed in phloem of petiole, subsectretory, and secretory cells of the secretory gland. These results suggested that the nectar moved by symplastic transport through the plasmodesmata. On the other hand, the nectar droplets were observed in the secretory cell walls. in the cuticular layer just beyond of the former, and on the outer surface of the cuticular layer: such observations indicated that a apoplastic movement was involved in the final step of the nectar secretion. Cellular components related to the nectar transport, such as plasma membrane, cell wall and cuticle were not destroyed but intact: it was interpreted as a eccrine secretion.retion.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1995.10a
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• pp.107-113
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• 1995

Basement membrane laminin is a multidomain glycoprotein that interacts with itself, heparin and cells. The distal long arm plays major cell and heparin interactive roles. The long arm consists of three subunits (A, B1, B2) joined in a coiled-coil rod attached to a terminal A chain globule (G). The globule is in turn subdivided into five subdomains (Gl-5). In order to analyze the functions of this region, recombinant G domains (rG, rAiG, rG5, rGΔ2980-3028) were expressed in Sf9 insect cells using a baculovirus expression vector. A hybrid molecule (B-rAiG), consisting of recombinant A chain(rAiG) and the authentic B chains (E8-B)was assembled in vitro. The intercalation of rAiG into E8-B chains suppressed a heparin binding activity identified in subdomain Gl-2. By the peptide napping and ligand blotting, the relative affinity of each subeomain to heparin was assigned as Gl> G2= G4> G5> G3, such that G1 bound strongly and G3 not at all. The active heparin binding site of G domain in intact laminin appears to be located in G4 and proximal G5. Cell binding was examined using fibrosarcoma Cells. Cells adhered to E8, B-rAiG, rAiG and rG, did not bind on denatured substrates, poorly bound to the mixture of E8-B and rG. Anti-${\alpha}$6 and anti-${\beta}$1 integrin subunit separately blocked cell adhesion on E8 and B-rAiG, but not on rAiG. Heparin inhibited cell adhesion on rAiG, partially on B-rAiG, and not on E8. In conclusion, 1) There are active and cryptic cell and heparin binding activities in G domain. 2) Triple-helix assembly inactivates cell and heparin binding activities and restores u6131 dependent cell binding activities.

• Membrane and Water Treatment
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• v.9 no.3
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• pp.181-188
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• 2018

A sidestream contains the filtrate or concentrate from the belt filter press, filter backwash and supernatant from sludge digesters. The sidestream flow, which heads back into the sewage treatment train, is about 1-3% less than the influent flow. However, the sidestream can increase the nutrient load since it contains high concentrations of phosphorus and nitrogen. In this study, the removal of PO4-P with organic matter characteristics and bacteriological changes during the sidestream treatment via ladle furnace (LF) slag was investigated. The sidestream used in this study consisted of 11-14% PO4-P and 3.2-3.6% soluble chemical oxygen demand in influent loading rates. LF slag, which had a relatively high $Ca^{2+}$ release compared to other slags, was used to remove $PO_4-P$ from the sidestream. The phosphate removal rates increased as the slag particle size decreased 19.1% (2.0-4.0 mm, 25.2% (1.0-2.0 mm) and 79.9% (0.5-1.0 mm). The removal rates of dissolved organic carbon, soluble chemical oxygen demand, color and aromatic organic matter ($UV_{254}$) were 17.6, 41.7, 90.2 and 77.3%, respectively. Fluorescence excitation-emission matrices and liquid chromatography-organic carbon detection demonstrated that the sidestream treatment via LF slag was effective in the removal of biopolymers. However, the removal of dissolved organic matter was not significant during the treatment. The intact bacterial biomass decreased from $1.64{\times}10^8cells/mL$ to $1.05{\times}10^8cells/mL$. The use of LF slag was effective for the removal of phosphate and the removal efficiency of phosphate was greater than 80% for up to 100 bed volumes.

• Journal of the Korean Arthroscopy Society
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• v.1 no.1
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• pp.112-115
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• 1997

While the cruciate ligament has a profuse vascular response following injury, spontaneous repair does not occur. This may result from the fact that synovial fluid dilution of the hematoma following injury prevents the formation of a fibrin clot and thus the initiation of the healing mechanism. Another theory suggests that the dynamic nature of the fascicles of the anterior cruciate ligament(ACL) through even small ranges of motion prohibits spontaneous union to these fibers. But we experienced two cases of spontaneous healing of partially injured ACL. Initially they showed more than grade II anterior instability. 6 mm difference by stress roentgenographs(pull view) and difference of 8 mm by KT 1000TM arthrometer between the ACL injured knee and normal side knee. Lax, nearly complete tear of ACL and synovial bleeding were noted during arthroscopic examination but the continuity of synovial membrane was seemed to be intact. These cases were treated by conservative management rather than reconstructive procedure. Postoperatively they showed excellent clinical results, no anterior instability and unlimited athletic activity. Based on our clinical experience. we think that cruciate ligament has the spontaneous healing potential in acute stage and middle aged patient. We consider the microfracture technique and initial immobilization for accelleration of healing response of the ACL.

• The Plant Pathology Journal
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• v.28 no.4
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• pp.401-408
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• 2012

Initial subcellular responses in susceptible (PI 274420) and resistant (cv. Hartwig) soybeans infected with the soybean cyst nematode (SCN) were examined 2 and 4 days after inoculation (DAI). Subcellular features common to both soybeans at 2 DAI included hypertrophied initial syncytial cells (ISCs) and syncytium-component cells (SCs) with a dense cytoplasm containing proliferated rough and smooth endoplasmic reticulum (RER and SER), a hypertrophied nucleolus, and reduced vacuoles, suggesting that the nematode-infected cells were dedifferentiated. In the resistant soybean, a striking initial subcellular difference from the susceptible soybean was the dilation of the RER, indicating ER dysfunction and leading to cell death. This disturbed nematode feeding, as evidenced by disrupted feeding tubes. In PI 274420, the ISC cytoplasm was depleted, with the exception of ER membranes, at 4 DAI, while the SC cytoplasm was dense with proliferation of starch-containing plastids around multiple nuclei that might be derived from the congregation of nuclei in the neighboring SCs and in part by nuclear division without cytokinesis. In cv. Hartwig, syncytia were necrotized with secondary cell wall thickening outside the plasma membrane and an extremely dense cytoplasm containing a nucleus with an electron-lucent nucleolus, accompanied by the proliferation of closely stacked parallel RER and ribosomes. These results suggest that syncytia develop continuously in PI 274420 to produce and store nutritional substances in SCs, providing for the nematode through ISC until maturation, but in cv. Hartwig, syncytia degenerate early due to excessive metabolism, blocking nematode feeding and cytoplasmic connections with adjacent intact cells.