• Title/Summary/Keyword: Cellular transport

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Sub-Optimal Route Planning by Immuno-Agents

  • Takakazu, Ishimatsu;Chan, Tony
    • 제어로봇시스템학회:학술대회논문집
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    • 2001.10a
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    • pp.89.6-89
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    • 2001
  • In Vehicle Information and Communication System (VICS), which is an active field of Intelligent Transport System (ITS), information of traffic congestion is sent to each vehicle at real time. However, a centralized navigation system is not realistic to guide millions of vehicles in a megalopolis. Autonomous distributed systems should be more flexible and scalable, and also have a chance to focus on each vehicle´s demand. This paper proposes a sub-optimal route planning mechanism of vehicles in urban areas using the non-network type immune system. Simulation is carried out using a cellular automaton model. This system announces a sub-optimal route to drivers in real time using VICS.

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Large Conformational Changes and Molecular Recognition in Signal Transduction: Calmodulin and Active Transport/Chemosensory Receptors

  • QUIOCHO, FLORANTE A.
    • Proceedings of the Korean Biophysical Society Conference
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    • 1997.07a
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    • pp.9-10
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    • 1997
  • Calmodulin: very large conformation change of helix uncoiling, hinge-bending and domain rotation. Calmodulin (CaM) is the principal Ca$\^$2+/ -dependent regulator of a variety of important eukaryotic cellular processes. In many of these processes, calmodulin activates a plethora of target enzymes, and the calmodulin-binding domains in several targets have been shown to residue in a region of about 18-residue peptide segment.(omitted)

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Solute Carrier SLC41A1 'A MINI REVIEW'

  • Basnet Hom Bahadur
    • Environmental Mutagens and Carcinogens
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    • v.25 no.2
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    • pp.60-65
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    • 2005
  • The human solute carrier, SLC41Al, is a $Mg^{2}+$ transporter that is regulated by extracellular magnesium. Although intracellular magnesium plays a fundamental role in cellular metabolism, little is known about how $Mg^{2}+$ is taken up and controlled by cells. Magnesium plays a fundamental role in cellular metabolism so that its control within the body is critical. Magnesium homeostasis is principally a balance between intestinal absorption of dietary magnesium and renal excretion of urinary magnesium. The kidney, mainly the distal convoluted tubule, controls magnesium reabsorption. Although renal reabsorption is under the influence of many hormones, selective regulation of magnesium transport is due to intrinsic control involving transcriptional processes and synthesis of transport proteins. Using microarray analysis, identification of the genetic elements involved with this transcriptional control has been begun. SLC41A1(GenBank Accession No. AJ514402), comprises 10 putative transmembrane domains, two of which are highly homologous to the integral membrane part of the prokaryote transports $Mg^{2}+$ and other divalent cations $Sr^2+,\;Zn^2+,\;Cu^2+,\;Fe^2+,\;Co^2+,\;Ba^2+,\;and\;Cd^2+,\;but\;not\;Ca^2+,\;Mn^2+,\;and\;Ni^2+.$ Transport of $Mg^{2}+$ by SLC41Al is rheogenic, voltage dependent, and not coupled to Na or Cl. Expressed SLC41Al transports a range of other divalent cations: $Mg^{2+},\;Sr^{2+},\;Zn^{2+},\;Cu^{2+},\;Fe^{2+},\;Co^{2+},\;Ba^{2+},\;and\;Cd^{2+}$. The divalent cations $Ca^{2+},\;Mn^{2+},\;and\;Ni^{2+}$and the trivalent ion $Gd^{3+}$ did not induce currents nor did they inhibit $Mg^{2+}$ transport. The nonselective cation $La^{3+}$ abolishes $Mg^{2+}$ uptake. Computer analysis of the SLC41Al protein structure reveals that it belongs to MgtE protein family & suggested that the human solute carrier, SLC41Al, might be a eukaryotic $Mg^{2+}$ transporter closely related $(60-70\%)$ protein encoded by SLC41A2 is a $Mg^{2}+$ transporter that might be involved in magnesium homeostasis in epithelial cells also transports a range of other divalent cations: $Ba^2,\;Ni^2,\;CO^2,\;Fe^2,\;or\;Mn^2,\;but\;not\;Ca^2,\;Zn^2,\;or\;Cu^{2+}$ that may have related functional properties.

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Identification of SNPs in Cellular Retinol Binding Protein 1 and Cellular Retinol Binding Protein 3 Genes and Their Associations with Laying Performance Traits in Erlang Mountainous Chicken

  • Wang, Yan;Xiao, Li-Hua;Zhao, Xiao-Ling;Liu, Yi-Ping;Zhu, Qing
    • Asian-Australasian Journal of Animal Sciences
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    • v.27 no.8
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    • pp.1075-1081
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    • 2014
  • CRBP1 (cellular retinol binding protein 1) and CRBP3 (cellular retinol binding protein 3), are important components of the retinoid signaling pathway and take part in vitamin A absorption, transport and metabolism. Based on the role of vitamin A in chicken laying performance, we investigated the polymorphism of CRBP1 and CRBP3 genes in 349 chickens using single strand conformation polymorphism and DNA sequencing methods. Only one polymorphism was identified in the third intron of CRBP1, two polymorphisms were detected in CRBP3; they were located in the second intron and the third intron respectively. The association studies between these three SNPs and laying performance traits were performed in Erlang mountainous chicken. Notably, the SNP g.14604G>T of CRBP1 was shown to be significantly associated with body weight at first egg (BWFE), age at first egg (AFE), weight at first egg (WFE) and total number of eggs with 300 age (EN). The CRBP3 polymorphism g.934C>G was associated with AFE, and the g.1324A>G was associated with AFE and BWFE, but none of these polymorphisms were associated with egg quality traits. Haplotype combinations constructed on these two SNPs of CRBP3 gene were associated with BWFE and AFE. In particular, diplotype H2H2 had positive effect on AFE, BWFE, EN, and average egg-laying interval. We herein describe for the first time basic research on the polymorphism of chicken CRBP1 and CRBP3 genes that is predictive of genetic potential for laying performance in chicken.

Effects of 1,25 Dihydroxycholecalciferol and Ca Ionophore A23187 on Ca Transports in Bone and Bone Cells (뼈조직과 세포에서의 칼슘이동기전에 대한 1,25 dihydroxycholecaliciferol과 Ca Ionophore A23187의 영향)

  • 이선영
    • Journal of Nutrition and Health
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    • v.21 no.3
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    • pp.173-181
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    • 1988
  • Various types of evidence suggest that some changes in cellular in cellular calcium may well signal the initiation of a chain of events leading to the physiological effects of the bone resorbing agents. The effects of 1,25-dihydorxycholecalciferol, $1.25\textrm{(OH)}_2\textrm{D}_3$, Ca ionophore A23187 and calcium antagonist, diltiazem on bone resprption and the cellular transport of Ca were investigated. Bone $^{45}\textrm{Ca}$ desaturation experiment was realized in isolated heterogenous rat bone cells after equilibrating the cells with $^{45}\textrm{Ca}$. Results of $^{45}\textrm{Ca}$ desaturation experiments were analysed by fitting the $^{45}\textrm{Ca}$ desaturation curve to a model of 2 exponential terms which indicated the presence of 2 exchangeable cellular calcium pools. $1.25\textrm{(OH)}_2\textrm{D}_3$ (0.5ng/$m\ell$) induced significantly bone resorption which was decreased by the physiological dose of diltiazeme(above 5nmol/$m\ell$) although it was ineffective alone. Ionophore A23187 (0.2$\mu\textrm{g}$/$m\ell$) decreased Ca release from bone but no additivity of effect with diltiazem(20nmol/$m\ell$) was observed. $1.25\textrm{(OH)}_2\textrm{D}_3$ (0.5ng/$10^{6}$ cells) had a moderate effect on the two kinetic phases of $^{45}\textrm{Ca}$ desaturation curve and these values were normalized when diltiazeme (20nmol/$10^{6}$ cells) was added along with $1.25\textrm{(OH)}_2\textrm{D}_3$. Ionophore($0.05\mu\textrm{g}$/$10^{6}$ cells) alone increased specifically the value of the slow turnover rate which was not affected by addition of diltiazem. The hypothesis concerning the involvement of calcium in bone resorption seems in fact to be verified in case of $1.25\textrm{(OH)}_2\textrm{D}_3$ but more unsettled for Ca inophore A23187.

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EFFECT OF GINSENG SAPONIN ON THE VASCULAR SMOOTH MUSCLE

  • Lee Kwang Soo
    • Proceedings of the Ginseng society Conference
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    • 1980.09a
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    • pp.71-76
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    • 1980
  • Aortic strips were prepared from rabbits, and the tensions were maintained by administration of norepinephrine into the incubation chamber. The application of diol or triol induced relaxation of the aortic strip, as indicated by the decreased aortic tension. Triol, in a concentration of $30\;mg\%\;causes\;approximately\;50\%$ of muscle relaxation, whereas a similar degree of relaxation is induced by $50\;mg\%$ of diol. This indicates that both triol and diol cause relaxation of the aorta, but that triol is about $170\%$ more potent than diol. It is well established that blood-vessel smooth-muscle tone is regulated by the available intracellular $Ca^{++}$ concentration, which in turn is profoundly influenced by interaction of the cellular membrane and sarcoplasmic reticulum in the smooth muscle. Thus, any agent which modifies the smooth-muscle tone is expected to interfere with the $Ca^{++}$ binding or uptake of sarcolemma and sarcoplasmic reticulum. In the following experiments sarcoplasmic reticulum and sarcolemma were prepared from the ventricle of rabbit heart, and the active $Ca^{++}$ uptake by these cellular components was measured employing $Ca^{45}$ in the presence of triol and diol. It was found that the active $Ca^{++}$ uptake in the presence of ATP by sarcoplasmic reticulum was inhibited by both triol and diol. Panaxatriol, in a concentration of $80\;mg\;\%,$ inhibited $Ca^{++}$ uptake by $30\%,$ whereas panaxatriol in the same concentration inhibited uptake by $20\%.$ It is clear that triol is a more potent inhibitor of active $Ca^{++}$ transport in sarcoplasmic reticulum than diol. The $Ca^{++}$ binding of the cellular membrane was also studied employing Ca45 and milipore techniques. It was found that triol in a concentration of $80\;mg\;\%,$ decreased $Ca^{++}$ binding by $29\%.$ Diol in the same concentration decreased the binding by $17\%.$ It is clear that both triol and diol inhibit $Ca^{++}$ binding to the cellular membrane, but triol is approximately $180\%$ more potent than diol.

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Performance Evaluation of AAL Type 2 (AAL Type 2의 성능 평가)

  • Kwon, Se-Dong;Han, Man-Yoo;Park, Hyun-Min;Joo, Woo-Seok;Jun, Jong-Hun;Lee, Kang-Sun
    • The KIPS Transactions:PartC
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    • v.9C no.6
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    • pp.847-856
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    • 2002
  • Cellular network applications are growing drastically and this requires a fast and efficient transport method between the base station and the mobile switching center. One possible solution is to use ATM links. The low data rate and small-sized packets in the typical cellular applications imply that significant amount of link bandwidth would be wasted, if this small sized packet is carried by one ATM cell. For efficient operation for such cellular and low bit rate applications, a new type of ATM Adaptation Layer, AAL Type 2, has been proposed. In this paper, the principles of AAL Type 2 are briefly described along with the introduction of other alternatives which have formed the basis for this new AAL. The result from the simulation to study the performance of the AAL Type 2 is discussed from the view point of packet delay and ATM cell use efficiency. Due to the variable size of packets in this application, the fairness issue in serving variable sized packets is also discussed along with the effect of fair queueing algorithm implemented at AAL Type 2.

Expression of a Glutathione Reductase from Brassica rapa subsp. pekinensis Enhanced Cellular Redox Homeostasis by Modulating Antioxidant Proteins in Escherichia coli

  • Kim, Il-Sup;Shin, Sun-Young;Kim, Young-Saeng;Kim, Hyun-Young;Yoon, Ho-Sung
    • Molecules and Cells
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    • v.28 no.5
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    • pp.479-487
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    • 2009
  • Glutathione reductase (GR) is an enzyme that recycles a key cellular antioxidant molecule glutathione (GSH) from its oxidized form (GSSG) thus maintaining cellular redox homeostasis. A recombinant plasmid to overexpress a GR of Brassica rapa subsp. pekinensis (BrGR) in E. coli BL21 (DE3) was constructed using an expression vector pKM260. Expression of the introduced gene was confirmed by semi-quantitative RT-PCR, immunoblotting and enzyme assays. Purification of the BrGR protein was performed by IMAC method and indicated that the BrGR was a dimmer. The BrGR required NADPH as a cofactor and specific activity was approximately 458 U. The BrGR-expressing E. coli cells showed increased GR activity and tolerance to $H_2O_2$, menadione, and heavy metal ($CdCl_2$, $ZnCl_2$ and $AlCl_2$)-mediated growth inhibition. The ectopic expression of BrGR provoked the co-regulation of a variety of antioxidant enzymes including catalase, superoxide dismutase, glutathione peroxidase, and glucose-6-phosphate dehydrogenase. Consequently, the transformed cells showed decreased hydroperoxide levels when exposed to stressful conditions. A proteomic analysis demonstrated the higher level of induction of proteins involved in glycolysis, detoxification/oxidative stress response, protein folding, transport/binding proteins, cell envelope/porins, and protein translation and modification when exposed to $H_2O_2$ stress. Taken together, these results indicate that the plant GR protein is functional in a cooperative way in the E. coli system to protect cells against oxidative stress.

CrABCA2 Facilitates Triacylglycerol Accumulation in Chlamydomonas reinhardtii under Nitrogen Starvation

  • Jang, Sunghoon;Kong, Fantao;Lee, Jihyeon;Choi, Bae Young;Wang, Pengfei;Gao, Peng;Yamano, Takashi;Fukuzawa, Hideya;Kang, Byung-Ho;Lee, Youngsook
    • Molecules and Cells
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    • v.43 no.1
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    • pp.48-57
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    • 2020
  • The microalga Chlamydomonas reinhardtii accumulates triacylglycerols (TAGs) in lipid droplets under stress conditions, such as nitrogen starvation. TAG biosynthesis occurs mainly at the endoplasmic reticulum (ER) and requires fatty acid (FA) substrates supplied from chloroplasts. How FAs are transferred from chloroplast to ER in microalgae was unknown. We previously reported that an Arabidopsis thaliana ATP-binding cassette (ABC) transporter, AtABCA9, facilitates FA transport at the ER during seed development. Here we identified a gene homologous to AtABCA9 in the C. reinhardtii genome, which we named CrABCA2. Under nitrogen deprivation conditions, CrABCA2 expression was upregulated, and the CrABCA2 protein level also increased. CrABCA2 knockdown lines accumulated less TAGs and CrABCA2 overexpression lines accumulated more TAGs than their untransformed parental lines. Transmission electron microscopy showed that CrABCA2 was localized in swollen ER. These results suggest that CrABCA2 transports substrates for TAG biosynthesis to the ER during nitrogen starvation. Our study provides a potential tool for increasing lipid production in microalgae.

A Joint Resource Allocation and Routing Scheme for the IEEE 802.16j Multi-hop Relay Networks (IEEE 802.16j 멀티홉 릴레이 네트워크를 위한 통합 자원 할당-라우팅 기법)

  • Lee, Kyung-Joo;Lee, Hyuk-Joon
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.8 no.1
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    • pp.82-91
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    • 2009
  • Routing (or path selection) is one of the key issues of multi-hop relay networks such as the IEEE 802.16j. Moreover, the allocation of appropriate resource such as bandwidth should not only be made in accordance with the paths selected, but the utilization of radio resource of an entire cell should also be maximized. Due to this interdependency between the problems of resource allocation and routing, it is desired these two problems are addressed simultaneously. In this paper, we propose a joint resource allocation and routing scheme for an OFDMA-based multi-hop cellular system. This scheme uses a polynomial time heuristic algorithm called Multi-Dimensional Multi-choice Knapsack Problem (MMKP) in order to find an approximate solution maximizing the total downlink throughput. In the simulation results, we show that the proposed scheme finds a sub-optimal solution which is superior to a link quality-based routing scheme, but slightly worse than the optimal solution.

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