• Applied Microscopy
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• v.16 no.2
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• pp.35-48
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• 1986

Ultrastructures of the cutaneous xanthophores and formation of pigment granules in the goldfish, Carassius auratus L., are studied with electron microscope. The cutaneous xanthophores are observed only in dermis and pigment granules of these pigment cells are pterinosomes and carotenoid vesicles. By the differentiated level, pterinosomes are subdivided into 3 types; while type I pterinosomes have clear limiting membranes and contain some amorphous fine fibrous structures, type II pterinosomes have thick and densely aggregated fibrous materials. Type III pterinosomes have concentric lamellar structures in the granules. Pigment granules of the xanthophores are originated from the Golgi complexes and pinocytotic vesicles of plasma membrane as well as rER-rich cells among the chromatophores are presumed to be associated with the accumulation of pigment materials.

• BMB Reports
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• v.42 no.1
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• pp.1-5
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• 2009

Synaptic vesicles (SVs) are key structures for synaptic transmission in neurons. Numerous membrane-associated proteins are sorted from the Golgi complex to the axon and the presynaptic terminal. Protein-protein and protein-lipid interactions are involved with SV targeting in neurons. Interestingly, many SV proteins have lipid binding capability, primarily with either cholesterol or phosphoinositides (PIs). As examples, the major SV protein synaptophysin can bind to cholesterol, a major lipid component in SVs, while several other SV proteins, including synaptotagmin, can bind to PIs. Thus, lipid-protein binding plays a key role for the SV targeting of synaptic proteins. In addition, numerous SV proteins can be palmitoylated. Palmitoylation is thought to be another synaptic targeting signal. Here, we briefly describe the relationship between lipid binding and SV targeting.

• The Korean Journal of Zoology
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• v.39 no.2
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• pp.223-230
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• 1996

Fine structure of the neuromuscular junction in the venomous organ of the spider, Agelena li'mbutq, was studied using high magnification electron microscope. The motor nerve endings at neuromuscular contact area composed of neurons and neuroslial cells were located between musculature and extracellular sheath of the venom gBand. At the synaptic contact between a motor axon and a muscle fiber in the musculature, spherical synaptic vesicles were prominent in the nerve terminal. The sarcoplasm beneath the neuromuscular synapse has a granular appearance and lacks mvofilaments. And the main axon gives off a branch between the muscle fibers. The synaptic regions of this organ are located close to the myofilaments unlike to other chelicerate classes. Moreover the postsvnaptic complex of vesicles and membrane invasinations present in other synaptic legions are absent from these legions in this venomous organ.

• Journal of Microbiology and Biotechnology
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• v.27 no.4
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• pp.791-807
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• 2017

The type II secretion system (T2SS), which transports selected periplasmic proteins across the outer membrane, has rarely been studied in nonpathogens or in organisms classified as Betaproteobacteria. Therefore, we studied Cupriavidus metallidurans (Cme), a facultative chemilithoautotroph. Gel analysis of extracellular proteins revealed no remarkable differences between the wild type and the T2SS mutants. However, enzyme assays revealed that native extracellular alkaline phosphatase is a T2SS substrate, because activity was 10-fold greater for the wild type than a T2SS mutant. In Cme engineered to produce three Ralstonia solanacearum (Rso) exoenzymes, at least 95% of their total activities were extracellular, but unexpectedly high percentages of these exoenzymes remained extracellular in T2SS mutants cultured in rich broth. These conditions appear to permit an alternative secretion process, because neither cell lysis nor periplasmic leakage was observed when Cme produced a Pectobacterium carotovorum exoenzyme, and wild-type Cme cultured in minimal medium secreted 98% of Rso polygalacturonase, but 92% of this exoenzyme remained intracellular in T2SS mutants. We concluded that Cme has a functional T2SS despite lacking any abundant native T2SS substrates. The efficient secretion of three foreign exoenzymes by Cme is remarkable, but so too is the indication of an alternative secretion process in rich culture conditions. When not transiting the T2SS, we suggest that Rso exoenzymes are probably selectively packaged into outer membrane vesicles. Phylogenetic analysis of T2SS proteins supports the existence of at least three T2SS subfamilies, and we propose that Cme, as a representative of the Betaproteobacteria, could become a new useful model system for studying T2SS substrate specificity.

• Journal of Microbiology and Biotechnology
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• v.7 no.6
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• pp.378-385
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• 1997

Cation motive ATPases on cell membranes of Helicobacter pylori were investigated using everted membrane vesicles. Latent ATPases could be ascertained from aggregated vesicle using N, N-dimethylformamide (DMF) and Triton X-100. By contrast, ultrasonication or chloroform treatments caused membranes to be disrupted, resulting in an alteration of sensitivities against azide or vanadate. Considerable amounts of vanadate-sensitive enzymes were identified from vesicle micelles, prepared by the dilution method. These were activated in the presence of either $Ni^{2+}\;or\;NH_4^+$. From studies employing H. pylori intact cell systems, we found that ATPase expression of this bacterium was markedly dependent upon air composition. It was interesting that cellular expression of $Ni^{2+}$- or $NH_4^{+}$-motive ATPases was significantly affected by extracellular pH, suggesting that these unique enzymes may physiologically be involved in cellular $Ni^2$ import and $NH_4^+$ export, respectively.

• Applied Microscopy
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• v.28 no.1
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• pp.73-82
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• 1998

To elucidate how microfilaments and vesicles participate in bile formation, the pericanalicular cytoplasms were observed in the liver of rats treated with taurocholic acid by deep etching with rapid freezing, and copmpared them with the findings on convensional thin sections. The microfilaments were identified around the bile canaliculi in the forms of core filaments of microvilli, filaments of pericanalicular web running in parallel to the border of bile canaliculi, and filaments on the junctional complex. In taurocholic acid-treated rats, microfilaments could be visualized around the bile canaliculi and along their borders. The microfilaments appeared to be installed to link to both the canalicular membrane and vesicles. Such specialized microfilaments are considered to participate in the translocation of vesicles in the pericanalicular cytoplasm. From the evidence, it is assumed that the microfilament induces the vesicles to transport and fuse to bile canalicull into which bile acids is secreted by exocytosis.

• YAKHAK HOEJI
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• v.30 no.1
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• pp.31-41
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• 1986

Sarcolemmal membrane fraction from canine ventricle was isolated from the discarded pellet after the first homogenization in the isolation procedure of sarcoplasmic reticulum (Method 1) and the protein yield, purity, and sidedness of this preparation were compared to those of sarcolemmal fraction prepared by method of Lee et al. (Method 2) and a slight modification of original protocol of Jones et al. (Method 3). Method 1 differed from Method 2 essentially only in that vigorous homogenization was carried out by omnimixer and homogenization medium containing 30mM Tris-maleate was used in the first step. The sarcolemmal fraction was enriched from 45 to 50 and 29-fold in [$^3H$] ouabain, [$^3H$] DHA, [$^3H$] QNB binding and $Na^+$, $K^+$-ATPase activity, respectively, compared to homogenate. Total $Na^+$, $K^+$-ATPase activity of highly sarcolemma enriched fraction was 144.6$\pm$16.4$\mu\textrm{mol}$ Pi/mg protein/hr, which was about 85%, of total ATPase activity, and the yield of the preparation was 15.7 mg protein per 100g of starting ventricular tissue. The sarcolemmal preparation supported $^{45}Ca^{2+}$-uptake in the presence of ATP but this uptake was not dependent on oxalate. Sarcolemmal $Na^+$, $K^+$-ATPase activity and detectable [$^3H$] ouabain binding were increased about 32% and 35%, respectively, by pretreatment of sarcolemmal fraction with optimal concentration of sodium dodecylsulfate (0.3-0.4mg/mg protein), suggesting that this preparation contained about 24% of sealed rightside-out vesicles, 26% of sealed inside-out vesicles, and 5001o of freely permeable (leaky) form. This procedure showed the highest protein yield and leaky population, compared to Method 2 and 3. On the other hand, sarcolemmal fraction prepared by Method 2 and 3 showed low value in protein yield but comtained high population of inside-out (46%) and rightside-out (49%) vesicles, respectively, compared to present procedure (Method 1). The results indicate that vigorous homogenization decreases the population of sealed sarcolemmal vesicles but increases the sarcolemmal protein yield per gram tissue and that this procedure is available for further purification of sarcolemmal fraction and for the receptor binding study of sarcolemma.

• Journal of Biomedical Engineering Research
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• v.45 no.1
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• pp.20-25
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• 2024

Extracellular vesicles (EVs) are nano-sized lipid bilayer vesicles released by cells. EVs act as messengers for cell-to-cell communication. Inside, it contains various substances that show biological activity, such as proteins, lipids, nucleic acids, and metabolites. The study of EVs extracted from terrestrial organisms and stem cells on inflammatory environments and tissue regeneration have been actively conducted. However, marine organisms-derived EVs are limited. Therefore, we have extracted EVs from sea urchins belonging to the Echinoderm group with their excellent regenerative ability. First, we extracted extracellular matrix (ECM) from sea urchin gonads treated with hypotonic buffer, followed by collagenase treatment, and filtration to collect ECM-bounded EVs. The size of sea urchin gonad-derived EVs (UGEVs) is about 20-100 nm and has a round shape. The protein content was higher after EVs burst than before, which is evidence that proteins are contained inside. In addition, proteins of various sizes are distributed inside. PKH-26 was combined with UGEVs, which means that UGEVs have a lipid membrane. PHK-26-labeled UGEVs were successfully uptaken by cells. UGEVs can be confirmed to have the same characteristics as traditional EVs. Finally, it was confirmed that Schwann cells were not toxic by increasing proliferation after treatment.

• Journal of Microbiology and Biotechnology
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• v.27 no.12
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• pp.2173-2179
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• 2017

The intracytoplasmic membrane of Rhodobacter sphaeroides readily vesiculates when cells are lysed. The resulting chromatophore membrane vesicle (CMV) contains the photosynthetic machineries to synthesize ATP by ATPase. The light-dependent ATPase activity of CMV was lowered in the presence of $O_2$, but the activity increased to the level observed under anaerobic condition when the reaction mixture was supplemented with ascorbic acid (${\geq}0.5mM$). Cell lysis in the presence of biotinyl cap phospholipid (bcp) resulted in the incorporation of bcp into the membrane to form biotinylated CMV (bCMV), which binds to streptavidin resin at a ratio of approximately $24{\mu}g$ bacteriochlorophyll a/ml resin. The ATPase activity of CMV was not affected by biotinylation, but approximately 30% of the activity was lost by immobilization to resin. Interestingly, the remaining 70% of ATPase activity stayed constant during 7-day storage at $4^{\circ}C$. On the contrary, the ATPase activity of bCMV without immobilization gradually decreased to approximately 40% of the initial level in the same comparison. Thus, the ATPase activity of CMV is sustainable after immobilization, and the immobilized bCMV can be used repeatedly as an ATP generator.

• Journal of Life Science
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• v.28 no.4
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• pp.496-507
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• 2018

Immunization has been performed for centuries and is generally accepted as a sustainable method of controlling bacteria, viruses, and mediated and infectious diseases. Despite many studies having been performed on animal subjects to demonstrate the importance of toxin immunity, the use of toxoid vaccines in humans and animals has been limited for a long time. Recently, the development of the toxoid antigen delivery system has been facilitated using novel nano-medicinal technology. The micro/nano-carrier has been used to improve vaccination coverage as well as reduce vaccine costs. A micro/nano-carrier is a micro/nano-sized material that delivers immune cargo, including recombinant or peptide toxoid antigens. These toxoid antigens are either encapsulated in the interior or displayed on the surface of micro/nano-carriers as a way to protect them from the cellular machinery. In particular, the combination of toxoid antigens and micro/nano-carriers can induce phagocytosis through the specific interactions between GCs and macrophages; thus, the toxoid antigens can be delivered easily into the macrophages. This paper reviews recent achievements of micro/nano-carriers in the field of vaccine delivery systems such as microbial ghost cells (GCs, Bacterial ghost cells and Yeast ghost cells), gene-manipulated outer membrane vesicles (OMVs) and biocompatible, polymer-based nanoparticles (NPs, NP-Carrier and NP-Cage). Finally, this review shows various aspects in terms of the hosts' immune responses.