• ALGAE
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• v.37 no.1
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• pp.75-84
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• 2022

Intercellular nutrient and signal transduction are essential to sustaining multicellular organisms and maximizing the benefits of multicellularity. It has long been believed that red algal intercellular transport of macromolecules is prevented by the protein-rich pit plug within pit-connections, the only physical connection between cells. Fluorescein isothiocyanate-dextran and recombinant green fluorescence protein (rGFP) of various molecular sizes were injected into vegetative cells of Griffithsia monilis using a micromanipulator, and intercellular transport of the fluorescent probes was examined. Pit-connections were found to provide intercellular transport of tracers at rates comparable to plasmodesmata in other organisms. The time necessary for the transport to an adjacent cell was dependent on the molecular size and the direction of the transport. Fluorescent dextran of 3 kDa was transported to adjacent cells in 1-2 h after injection and migrated to all cells of the filament within 24 h, but fluorescent dextran of 10-20 kDa took 24 h to transfer to neighboring cells. The migration occurred faster towards adjacent reproductive cells and to apical cells than basally. Fluorescent tracers above 40 kDa and rGFP was not transported to neighboring cells, but accumulated near the pit plug. Our results suggest that pit-connections are conduit for macromolecules between neighboring cells and that these size-specific conduits allow intercellular communication between the vegetative cells of red algae.

• Polymer(Korea)
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• v.29 no.6
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• pp.543-548
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• 2005

Double-layered spheres play an important role in controlling drug delivery for pharmaceutical application, because of the low initial burst compared with single-layered spheres and targetable delivery to specific organ. But it has drawback in loading drug and controlling size. In this study, we developed double-layered spheres using relatively simple oil-in-water (O/W) solvent evaporation method witw/without ultrasonication and investigated the size variation of the double-layered microspheres on the contents of poly(lactide- co-glycolide) (PLGA). Double - layered spheres were char-acterized by scanning elecron microscope (SEM), camscope, and confocal fluorescence laser microscope (CFLM). Double-layered spheres showed smooth surfaces and obvious difference between core and corona by SEM observation and camscope. We observed the fluorescent core in the double-walled spheres composed of FlTC-dextran and PLGA using CFLM. It was found that the core of the microsphere was dextran and the corona of the fabricate microsphere was PLGA. Also, the more PLGA concentration, the more the size of the fabricating double-layered sphere observed.

• Journal of Yeungnam Medical Science
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• v.23 no.1
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• pp.26-35
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• 2006

Background: Luteolin, a flavone found in various Chinese herbal medicines is known to possess anti-inflammatory properties through its ability to inhibit various proinflammatory signaling pathways including NF-${\kappa}B$ and p38 MAPK. In this study, we investigated the potential therapeutic effect of luteolin on dextran sodium sulfate (DSS)-induced colitis. Materials and Methods: We used a transgenic mouse model expressing the enhanced green fluorescent protein (EGFP) under the transcriptional control of NF-${\kappa}B$ $cis$-elements. C57BL/6 NF-${\kappa}B^{EGFP}$ mice received 2.5% DSS in their drinking water for six days in combination with daily luteolin administration (1mg/kg body weight, 0.1ml vol, intragastric) or vehicle. NF-${\kappa}B$ activity was assessed macroscopically with a Charge-Coupled Device (CCD) camera and microscopically by confocal analysis. Results: A significant increase in the Disease Activity Index (DAI), histological score (p<0.05), IL-12 p40 secretion in colonic stripe culture (p<0.05) and EGFP expression was observed in luteolin and/or DSS-treated mice compared to water-treated mice. Interestingly, a trend toward a worse colitis (DAI, IL-12p40) was observed in luteolin-treated mice compared to non-treated DSS-exposed mice. In addition, EGFP expression (NF-${\kappa}B$ activity) strongly increased in the luteolin-treated mice compared to control mice. Confocal microscopy showed that EGFP positive cells were primarily lamina propria immune cells. Conclusions: These results suggest that luteolin is not a therapeutic alternative for intestinal inflammatory disorders derived for primary defects in barrier function. Thus, therapeutic intervention targeting these signaling pathways should be viewed with caution.

• The Korean Journal of Urological Oncology
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• 제15권3호
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• pp.178-186
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• 2017

Purpose: Poloxamer 407 (P407) thermo-sensitive hydrogel formulations were developed to enhance the retention time in the urinary bladder after intravesical instillation. Materials and Methods: P407 hydrogels (P407Gels) containing 0.2 w/w% fluorescein isothiocyanate dextran (FD, MW 4 kDa) as a fluorescent probe were prepared by the cold method with different concentrations of the polymer (20, 25, and 30 w/w%). The gel-forming capacities were characterized in terms of gelation temperature (G-Temp), gelation time (G-Time), and gel duration (G-Dur). Homogenous dispersion of the probe throughout the hydrogel was observed by using fluorescence microscopy. The in vitro bladder simulation model was established to evaluate the retention and drug release properties. P407Gels in the solution state were administered to nude mice via urinary instillation, and the in vivo retention behavior of P407Gels was visualized by using an in vivo imaging system (IVIS). Results: P407Gels showed a thermo-reversible phase transition at $4^{\circ}C$ (refrigerated; sol) and $37^{\circ}C$ (body temperature; gel). The G-Temp, G-Time, and G-Dur of FD-free P407Gels were approximately $10^{\circ}C-20^{\circ}C$, 12-30 seconds, and 12-35 hours, respectively, and were not altered by the addition of FD. Fluorescence imaging showed that FD was spread homogenously in the gelled P407 solution. In a bladder simulation model, even after repeated periodic filling-emptying cycles, the hydrogel formulation displayed excellent retention with continuous release of the probe over 8 hours. The FD release from P407Gels and the erosion of the gel, both of which followed zero-order kinetics, had a linear relationship ($r^2=0.988$). IVIS demonstrated that the intravesical retention time of P407Gels was over 4 hours, which was longer than that of the FD solution (<1 hour), even though periodic urination occurred in the mice. Conclusions: FD release from P407Gels was erosion-controlled. P407Gels represent a promising system to enhance intravesical retention with extended drug delivery.