• Journal of Sericultural and Entomological Science
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• v.38 no.1
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• pp.42-47
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• 1996

To investigate the host range determining factors of nuclear polyhedrois virus (NPV), Autographa california NPV and Bombyx mori NPV were coinfected into the two different cell lines, BmN-4 and Sf-9. The recombinant baculoviruses, RecS-A6 and RecB-727 which have an expanded host range, were isolated from Sf-9 and BmN-4 cell lines, respectively. The molecular biological characteristics of the recombinant baculoviruses were investigated. The pathogenicity of RecB-727 was similar to that of wild type BmNPV, while the pathogenicity of RecS-A6 was relatively lower than that of wild type BmNPV. The restriction enzyme digestion patterns of parental viruses and recombinant viruses showed that the recombinant virus has an expanded host range by genetic recombination. Southern blot analysis revealed that the p10 gene of RecB-727 was derived from AcNPV genomic DNA, while RecS-A6 has p10 gene of BmNPV in a viral genome. To investigate the host range expansion mechanism of recombinant baculovirus, HindIII-SacI 0.6 kb DNA fragments of RecS-A6 and RecB-727 were cloned and sequenced. The results showed that of wild type BmNPV helicase gene, suggesting that the expanded host range of recombinant baculoviruses was due to the insertion of BmNPV helicase gene into AcNPV viral genome.

• Korean Journal of Poultry Science
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• v.16 no.1
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• pp.1-8
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• 1989

This experiment was conducted to improve the performance of chickens by the precise separation and analysis of chromosomes which are integrated genetic materials, and by the use of gene manipulation techniques. Following are the main results obtained. 1. When the chromosomes were separated through the leucocyte culture and analyzed by Giemsa banding techniques (especially by the method in which 20 layers of banding patterns could be found in chromosome ＃1), the normal Patterns of chromosomes ＃l-9 and sex chromosomes, and the location of constitutive heterochromatin without any gene activities in all chromosomes were discovered. 2. To utilize the primodial germ cells (PGC) as the genetic vector which is one of the most important gene manipulation techniques, PGC's from triploid were transplanted to normal host embryos. Since the donor PGC's(3n) were found in the gonads of growing host embryos gene manipulation in poultry using PGC's, seemed to be possible.

• Microbiology and Biotechnology Letters
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• v.29 no.1
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• pp.1-11
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• 2001

Lactic acid bacteria (LAB) are widely used for various food fermentation. With the recent advances in modern biotechnology, a variety of bio-products with the high economic values have been produced using microorganisms. For molecular cloning and expression studies on the gene of interest, E. coli has been widely used mainly because vector systems are fully developed. Most plasmid vectors currently used for E, coli carry antibiotic-resistant markers. As it is generally believed that the antibiotic resistance markers are potentially transferred to other bacteria, application of the plasmid vectors carrying antibiotic resistance genes as selection markers should be avoided, especially for human consump-tion. By contrast, as LAB have some desirable traits such that the they are GRAS(generally recognized as safe), able to secrete gene products out of cell, and their low protease activities, they are regarded as an ideal organism for the genetic manipulation, including cloning and expression of homologous and heterologous genes. However, the vec-tor systems established for LAB are stil insufficient to over-produce gene products, stably, limiting the use of these organisms for industrial applications. For a past decade, the two popular plasmid vectors, pAM$\beta$1 of Streptococcus faecalis and pGK12 theB. subtilis-E. coli shuttle vector derived from pWV01 of Lactococcus lactis ssp. cremoris wg 2, were most widely used to construct efficient chimeric vectors to be stably maintained in many industrial strains of LAB. Currently, non-antibiotic markers such as nisin resistance($Nis^{r}$ ) are explored for selecting recombi-nant clone. In addition, a gene encoding S-layer protein, slp/A, on bacterial cell wall was successfully recombined with the proper LAB vectors LAB vectors for excretion of the heterologous gene product from LAB Many food-grade host vec-tor systems were successfully developed, which allowed stable integration of multiple plasmid copies in the vec-mosome of LAB. More recently, an integration vector system based on the site-specific integration apparatus of temperate lactococcal bacteriophage, containing the integrase gene(int) and phage attachment site(attP), was pub-lished. In conclusion, when various vector system, which are maintain stably and expressed strongly in LAB, are developed, lost of such food products as enzymes, pharmaceuticals, bioactive food ingredients for human consump-tion would be produced at a full scale in LAB.

• Journal of KIISE:Information Networking
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• v.27 no.1
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• pp.88-97
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• 2000

Applied with multicast transmission techniques in mobile computing environments, a mobile host will experience join and graft delay, happened when a host wants to join a multicast group in the fixed network, if there are no same multicast group member in the new cell the mobile host enters. Due to low bandwidth and higher error rate, there happens many additional traffic. In this paper, we propose a pre-join technique which new mobile support station joins the multicast group in advance based on signal strength hint in the current cell. We use the multiple level acknowledgement strategy that executes acknowledgment separately between the fixed part and the wireless transmission path. Using our strategy, it is an efficient technique in case there are more cells that has no multicast group members and less mobile host movements.

• Korean journal of applied entomology
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• v.5_6
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• pp.9-18
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• 1968

Morphological studios on the mouth parts of some aphids belonging to 5 sub-families and on the penetration of stylets into their host plants were carried out in order to find out possible relationship between mouth parts and capability of virus transmission. 1. There were no differences between the aphid species in general morphology of mouth parts. 2. Mouth parts could be observed in detail especially in Toxoptera citricidus and Chaitophorus chinensis. 3. Accessory salivary gland was larger than principal salivary gland in Toxoptera citricidus. 4. In 4 species, e. g. Chaitophorus chinensis, Myzus persicae, Aphis craccivora, Toxoptem citricidus, the stylets were usually inserted in plant tissues intercellularly and reached phloem, however, in Lachnus tropicalis only intracellularly and in Eriosoma clemalis more frequently intracellularly. 5. The stylets tracks of Eriosoma clemalis, Lachnus tropicalis and Myzus persicae were clearly visible but not in Toxoptera citricidus, Chaitophorus chinensis and Aphis craccivora. The tracks were stained with yellowish brown or red brown. 6. Saliva was seceted between the cell walls in most species and some substances in saliva seem to cause loosend cell walls. 7. The penetration of the stylets might cause physiological disturbance to host plants and could make the host plants susceptible to the plant diseases.

• IMMUNE NETWORK
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• v.13 no.4
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• pp.133-140
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• 2013

Since the discovery of the immunomodulation property of mesenchymal stem cells (MSCs) about a decade ago, it has been extensively investigated whether MSCs can be used for the treatment of immune-related diseases, such as graft versus-host disease (GvHD). However, how to evaluate the efficacy of human MSCs for the clinical trial is still unclear. We used an MHC-mismatched model of GvHD (B6 into BALB/c). Surprisingly, the administration of the human MSCs (hMSCs) could reduce the GvHD-related mortality of the mouse recipients and xenogeneically inhibit mouse T-cell proliferation and $IFN-{\gamma}$ production in vitro. We recently established a new protocol for the isolation of a homogeneous population of MSCs called subfractionation culturing methods (SCM), and established a library of clonal MSC lines. Therefore, we also investigated whether MSCs isolated by the conventional gradient centrifugation method (GCM) and SCM show different efficacy in vivo. Intriguingly, clonal hMSCs (hcMSCs) isolated by SCM showed better efficacy than hMSCs isolated by GCM. Based on these results, the MHC-mismatched model of GvHD may be useful for evaluating the efficacy of human MSCs before the clinical trial. The results of this study suggest that different MSC lines may show different efficacy in vivo and in vitro.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.23
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• pp.10355-10361
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• 2015

Background: MicroRNAs (miRNAs) are small non-coding RNA molecules found in multicellular eukaryotes which are implicated in development of cancer, including cutaneous squamous cell carcinoma (cSCC). Expression is controlled by transcription factors (TFs) that bind to specific DNA sequences, thereby controlling the flow (or transcription) of genetic information from DNA to messenger RNA. Interactions result in biological signal control networks. Materials and Methods: Molecular components involved in cSCC were here assembled at abnormally expressed, related and global levels. Networks at these three levels were constructed with corresponding biological factors in term of interactions between miRNAs and target genes, TFs and miRNAs, and host genes and miRNAs. Up/down regulation or mutation of the factors were considered in the context of the regulation and significant patterns were extracted. Results: Participants of the networks were evaluated based on their expression and regulation of other factors. Sub-networks with two core TFs, TP53 and EIF2C2, as the centers are identified. These share self-adapt feedback regulation in which a mutual restraint exists. Up or down regulation of certain genes and miRNAs are discussed. Some, for example the expression of MMP13, were in line with expectation while others, including FGFR3, need further investigation of their unexpected behavior. Conclusions: The present research suggests that dozens of components, miRNAs, TFs, target genes and host genes included, unite as networks through their regulation to function systematically in human cSCC. Networks built under the currently available sources provide critical signal controlling pathways and frequent patterns. Inappropriate controlling signal flow from abnormal expression of key TFs may push the system into an incontrollable situation and therefore contributes to cSCC development.

• The Korean Journal of Physiology and Pharmacology
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• v.20 no.1
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• pp.63-67
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• 2016

Severe graft-versus-host disease (GVHD) is an often lethal complication of allogeneic hematopoietic stem cell transplantation (HSCT). The safety of clinical-grade mesenchymal stem cells (MSCs) has been validated, but mixed results have been obtained due to heterogeneity of the MSCs. In this phase I study, the safety of bone marrow-derived homogeneous clonal MSCs (cMSCs) isolated by a new subfractionation culturing method was evaluated. cMSCs were produced in a GMP facility and intravenously administered to patients who had refractory GVHD to standard treatment resulting after allogeneic HSCT for hematologic malignancies. After administration of a single dose ($1{\times}10^6cells/kg$), 11 patients were evaluated for cMSC treatment safety and efficacy. During the trial, nine patients had 85 total adverse events and the rate of serious adverse events was 27.3% (3/11 patients). The only one adverse drug reaction related to cMSC administration was grade 2 myalgia in one patient. Treatment response was observed in four patients: one with acute GVHD (partial response) and three with chronic GVHD. The other chronic patients maintained stable disease during the observation period. This study demonstrates single cMSC infusion to have an acceptable safety profile and promising efficacy, suggesting that we can proceed with the next stage of the clinical trial.

• Parasites, Hosts and Diseases
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• v.49 no.1
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• pp.1-8
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• 2011

The pathogenesis and pathophysiology of Acanthamoeba infections remain incompletely understood. Phospholipases are known to cleave phospholipids, suggesting their possible involvement in the host cell plasma membrane disruption leading to host cell penetration and lysis. The aims of the present study were to determine phospholipase activities in Acanthamoeba and to determine their roles in the pathogenesis of Acanthamoeba. Using an encephalitis isolate (T1 genotype), a keratitis isolate (T4 genotype), and an environmental isolate (T7 genotype), we demonstrated that Acanthamoeba exhibited phospholipase $A_2$ (PLA$_2$). and phospholipase D (PLD) activities in a spectrophotometry-based assay. Interestingly, the encephalitis isolates of Acanthamoeba exhibited higher phospholipase activities as compared with the keratitis isolates, but the environmental isolates exhibited the highest phospholipase activities. Moreover, Acanthamoeba isolates exhibited higher PLD activities compared with the PLA$_2$. Acanthamoeba exhibited optimal phospholipase activities at $37^{\circ}C$ and at neutral pH indicating their physiological relevance. The functional role of phospholipases was determined by in vitro assays using human brain microvascular endothelial cells (HBMEC), which constitute the blood-brain barrier. We observed that a PLD-specific inhibitor, i.e., compound 48/80, partially inhibited Acanthamoeba encephalitis isolate cytotoxicity of the host cells, while PLA$_2$-specific inhibitor, i.e., cytidine 5'-diphosphocholine, had no effect on parasite-mediated HBMEC cytotoxicity. Overall, the T7 exhibited higher phospholipase activities as compared to the T4. In contract, the T7 exhibited minimal binding to, or cytotoxicity of, HBMEC.

• Proceedings of the IEEK Conference
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• 2001.06a
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• pp.285-288
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• 2001

In this paper, we propose strategies that eliminating packet loss and minimize delay time during handoff under wireless LAN environments. As a mobile host moves between cells, a handoff takes place. A few handoff protocol have been proposed to eliminate the packet loss, but they have a heavy overhead. So, We proposed handoff protocol using the next-cell prediction scheme that send not to current BS but to mobile host and next BS, therefore next BS buffered packet send mobile host after handoff. We also present simulation results for our simulation using the Network Simulator (ns2). The simulations show that our handoff scheme is no packet loss.