• Journal of Microbiology and Biotechnology
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• v.17 no.1
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• pp.146-153
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• 2007

A mathematical competition model between normal flora and an invading pathogen was devised to allow analysis of bacterial infections in a host. The normal flora includes the various microorganisms that live on or within the host and act as a primary human immune system. Despite the important role of the normal flora, no mathematical study has been undertaken on models of the interaction between it and invading pathogens against a background of antibiotic treatment. To quantify key elements of bacterial behavior in a host, pairs of nonlinear differential equations were used to describe three categories of human health conditions, namely, healthy, latent infection, and active infection. In addition, a cutoff value was proposed to represent the minimum population level required for survival. The recovery of normal flora after antibiotic treatment was also included in the simulation because of its relation to human health recovery. The significance of each simulation parameter for the bacterial growth model was investigated. The devised simulation showed that bacterial proliferation rate, carrying capacity, initial population levels, and competition intensity have a significant effect on bacterial behavior. Consequently, a model was established to describe competition between normal flora and an infiltrating pathogen. Unlike other population models, the recovery process described by the devised model can describe the human health recovery mechanism.

• Journal of Microbiology and Biotechnology
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• v.29 no.12
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• pp.2014-2021
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• 2019

Middle East respiratory syndrome coronavirus (MERS-CoV) belongs to the genus Betacoronavirus and causes severe morbidity and mortality in humans especially when infected patients have underlying diseases such as chronic obstructive pulmonary disease (COPD). Previously, we demonstrated that MERS-CoV-encoded ORF8b strongly inhibits MDA5- and RIG-I-mediated induction of the interferon beta (IFN-β) promoter activities. Here, we report that ORF8b seemed to regulate MDA5 or RIG-I differentially as protein levels of MDA5 were significantly down-regulated while those of RIG-I were largely unperturbed. In addition, ORF8b seemed to efficiently suppress phosphorylation of IRF3 at the residues of 386 and 396 in cells transfected with RIG-I while total endogenous levels of IRF3 remained largely unchanged. Furthermore, ORF8b was able to inhibit all forms of RIG-I; full-length, RIG-I-1-734, and RIG-I-1-228, the last of which contains only the CARD domains. Taken together, it is tempting to postulate that ORF8b may interfere with the CARD-CARD interactions between RIG-I and MAVS. Further detailed analysis is required to delineate the mechanisms of how ORF8b inhibits the MDA5/RIG-I receptor signaling pathway.

• International Journal of Aeronautical and Space Sciences
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• v.18 no.4
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• pp.623-640
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• 2017

The full nonlinear equations of an unmanned aerial vehicle ground taxiing mathematical dynamic model are built based on a type of unmanned aerial vehicle data in LMS Virtual.Lab Motion. The flexible landing gear model is considered to make the aircraft ground motion more accurate. The electric braking control system is established in MATLAB/Simulink and the experiment of it verifies that the electric braking model with the pressure sensor is fitted well with the actual braking mechanism and it ensures the braking response speediness. The direction rectification control law combining the differential brake and the rudder with 30% anti-skid brake is built to improve the directional stability. Two other rectifying control laws are demonstrated to compare with the designed control law to verify that the designed control is of high directional stability and high braking efficiency. The lateral displacement increases by 445.45% with poor rectification performance under the only rudder rectifying control relative to the designed control law. The braking distance rises by 36m and the braking frequency increases by 85.71% under the control law without anti-skid brake. Different landing conditions are simulated to verify the good robustness of the designed rectifying control.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.7
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• pp.239-244
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• 2018

Both arterial dissection and atherosclerosis are major causes of cerebral infarction and appear to be occlusion or stenosis in magnetic resonance angiography(MRA) and computed tomographic angiography(CTA). But there are differences in treatment because they have different mechanisms. Recently, as high resolution magnetic resonance image(HR-MRI) develops, the image of blood vessel wall can be confirmed non-invasively. Though HR-MRI has become a very useful method for patients with suspected arterial dissection, differential diagnosis of the two diseases has not yet been fully established due to differences in the findings according to stages of arterial dissection and atherosclerosis. We investigated the differences between vertebral artery dissection and atherosclerosis through HR-MRI in two patients and confirmed the diagnosis by CTA follow-up. In addition to the previously established diagnostic criteria, we determined that the long and severe stenosis and recanalization suggest arterial dissection. Characteristics of arterial dissection confirmed by HR-MR and additional studies will be helpful for the treatment.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.5
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• pp.768-774
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• 2007

To study the effect of dietary docosahexaenoic acid (DHA) enrichment on the expression of hepatic genes in pigs, weaned, crossbred pigs (30 d old) were fed diets supplemented with either 2% tallow or DHA oil for 18 d. Hepatic mRNA was extracted. Suppression subtractive hybridization was used to explore the hepatic genes that were specifically regulated by dietary DHA enrichment. After subtraction, we observed 288 cDNA fragments differentially expressed in livers from pigs fed either 2% DHA oil or 2% tallow for 18 d. After differential screening, 7 genes were found to be differentially expressed. Serum amyloid A protein 2 (SAA2) was further investigated because of its role in lipid metabolism. Northern analysis indicated that hepatic SAA2 was upregulated by dietary DHA enrichment (p<0.05). In a second experiment, feeding 10% DHA oil for 2d significantly increased the expression of SAA2 (compared to the 10% tallow group; p<0.05). The porcine SAA2 full length cDNA sequence was cloned and the sequence was compared to the human and mouse sequences. The homology of the SAA2 amino acid sequence between pig and human was 73% and between pig and mouse was 62%. There was a considerable difference in SAA2 sequences among these species. Of particular note was a deletion of 8 amino acids, in the pig compared to the human. This fragment is a specific characteristic for the SAA subtype that involved in acute inflammation reaction. Similar to human and mouse, porcine SAA2 was highly expressed in the liver of pigs. It was not detectable in the skeletal muscle, heart muscle, spleen, kidney, lung, and adipose tissue. These data suggest that SAA2 may be involved in mediation of the function of dietary DHA in the liver of the pig, however, the mechanism is not yet clear.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.3
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• pp.336-342
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• 2009

Avian embryos at high altitude are independent of maternal protection against hypoxia, which is contrary to mammals. It is well known that chronic hypoxic exposure at key points can significantly impact on avian development. Tibetan Chicken, a Chinese indigenous breed, living in Tibetan areas with an altitude of 2.2 to 4.1 thousand meters, has an adaptive mechanism to hypoxia. In the present study, fertilized eggs of Tibetan Chicken were incubated under 13% and 21% oxygen concentration. Two lowland chicken breeds, Shouguang Chicken, an indigenous chicken breed in Shandong Province of China, and Dwarf Recessive White Chicken, an imported breed in Beijing, were used as control groups. The embryo mass and some organs such as brain, heart, liver, stomach and eye weight in the three species were measured at Hamburger-Hamilton stage 39, 41, 43 and 45 under hypoxic and normal conditions. The results showed that in hypoxia Tibetan Chicken significantly differed from the two lowland chicken breeds in embryo mass at Hamburger-Hamilton stage 41, 43 and 45 (p<0.01). In particular, Dwarf Recessive White Chicken and Shouguang Chicken showed retarded growth in hypoxic incubation (p<0.01), whereas Tibetan Chicken showed no significant difference between hypoxic and normal conditions (p>0.05). In addition, heart and the other organs showed different susceptibility to hypoxia at the studied stages. In conclusion, chronic hypoxia induced a change in the embryo development of the three different species and Tibetan Chicken showed adaptation to hypoxia. Of note, the embryo developmental physiology of Tibetan Chicken in response to hypoxia will shed light on the process of physiological acclimation or evolutionary adaptation as well as the study of clinical disease.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.8
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• pp.1091-1101
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• 2009

In an attempt to understand the biochemical mechanism for the synthesis of the anabolic steroid, 19-nortestosterone, produced by prepubertal boar testes and its physiological role, normalized complementary DNA (cDNA) from boar testes was generated. DNA sequencing of 2,016 randomly selected clones yielded 794,116 base pairs of high quality nucleotide sequence. Computer-assisted assembly of the nucleotide sequence of each clone resulted in 423 contigs and 403 singletons including several genes for steroidogenic enzymes and molecules related to steroid metabolism. Analysis of gene expression pattern by use of the presently-fabricated cDNA microarray identified a number of genes that were differentially expressed during the postnatal development period in boar testes. Two genes of unknown function were identified to be highly expressed in the testis of 2-weeks-old neonatal boar. In addition, the sequencing of open reading frames of these genes revealed their homology with human alpha hemoglobin and Homo sapiens hypothetical LOC643669, transcript variant 1. Moreover, the transcripts of these genes were also detected in porcine muscle and adipocytes, in addition to Leydig cells of pigs.

• Journal of Conservation Science
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• v.21
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• pp.33-40
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• 2007

The consolidation application of SILRES BS OH 100 was investigated, which has been used for consolidation of the weathered shale. The liquid SILRES BS OH 100 was polymerized by the sol-gel reaction with air moisture, and the XRD patterns showed that the gel was an amorphous solid. The drastic weight reduction of the sample was found by differential thermal analysis, which was followed to the formation of $Si(OH)_4$ particles. After consolidation, the polymerized gel was filled into the voids within the shale. The capillary water absorption of the consolidated shale was reduced to 48.7%, and the abrasive strength was improved.

• Journal of Microbiology and Biotechnology
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• v.25 no.10
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• pp.1606-1613
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• 2015

Porcine pleuropneumonia is an infectious disease caused by Actinobacillus pleuropneumoniae. The identification of A. pleuropneumoniae genes, specially expressed in vivo, is a useful tool to reveal the mechanism of infection. IVIAT was used in this work to identify antigens expressed in vivo during A. pleuropneumoniae infection, using sera from individuals with chronic porcine pleuropneumonia. Sequencing of DNA inserts from positive clones showed 11 open reading frames with high homology to A. pleuropneumoniae genes. Based on sequence analysis, proteins encoded by these genes were involved in metabolism, replication, transcription regulation, and signal transduction. Moreover, three function-unknown proteins were also indentified in this work. Expression analysis using quantitative real-time PCR showed that most of the genes tested were up-regulated in vivo relative to their expression levels in vitro. IVI (in vivo-induced) genes that were amplified by PCR in different A. pleuropneumoniae strains showed that these genes could be detected in almost all of the strains. It is demonstrated that the identified IVI antigen may have important roles in the infection of A. pleuropneumoniae.

• Journal of Microbiology and Biotechnology
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• v.25 no.7
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• pp.1056-1069
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• 2015

Osmotic pressure is a critical factor for erythritol production with osmophilic yeast. Protein expression patterns of an erythritol-producing yeast, Yarrowia lipolytica, were analyzed to identify differentially-expressed proteins in response to osmotic pressure. In order to analyze intracellular protein levels quantitatively, two-dimensional gel electrophoresis was performed to separate and visualize the differential expression of the intracellular proteins extracted from Y. lipolytica cultured under low (3.17 osmol/kg) and high (4.21 osmol/kg) osmotic pressures. Proteomic analyses allowed identification of 54 differentially-expressed proteins among the proteins distributed in the range of pI 3-10 and 14.4-97.4 kDa molecular mass between the osmotic stress conditions. Remarkably, the main proteins were involved in the pathway of energy, metabolism, cell rescue, and stress response. The expression of such enzymes related to protein and nucleotide biosynthesis was inhibited drastically, reflecting the growth arrest of Y. lipolytica under hyperosmotic stress. The improvement of erythritol production under high osmotic stress was due to the significant induction of a range of crucial enzymes related to polyols biosynthesis, such as transketolase and triosephosphate isomerase, and the osmotic stress responsive proteins like pyridoxine-4-dehydrogenase and the AKRs family. The polyols biosynthesis was really related to an osmotic response and a protection mechanism against hyperosmotic stress in Y. lipolytica. Additionally, the high osmotic stress could also induce other cell stress responses as with heat shock and oxidation stress responses, and these responsive proteins, such as the HSPs family, catalase T, and superoxide dismutase, also had drastically increased expression levels under hyperosmotic pressure.