• Title, Summary, Keyword: chemotaxis

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Isolation of Caenorhabditis elegans Mutants Defective in Chemotaxis toward cAMP

  • Jeong, Jin-A;Cho, Nam-Jeong
    • Animal cells and systems
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    • v.10 no.4
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    • pp.237-241
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    • 2006
  • Chemotactic behavior is essential for the survival of animals. However, the mechanism by which animals carry out chemotaxis is poorly understood. To explore the biochemical events underlying chemotaxis, we isolated C. elegans mutants that displayed abnormal chemotactic responses to cAMP, a strong attractant for C. elegans. Based on their responses to other chemoattractants, the mutant animals could be classified into five groups: (1) animals with defective chemotaxis to cAMP only; (2) animals with defective chemotaxis to both cAMP and cGMP; (3) animals with defective chemotaxis to water-soluble attractants; (4) animals with defective chemotaxis to both water-soluble and volatile attractants; and (5) animals with enhanced chemotactic responses. We expect that analyses of these mutants will help understand the molecular mechanisms underlying chemotaxis in C. elegans.

Development of a Three-Dimensional Chemotaxis Model for a Single Bacterium (3 차원 모델을 통한 단일 박테리아의 주화성 연구)

  • Song, Ji-Hwan;Kim, Dong-Choul
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.33 no.1
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    • pp.56-63
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    • 2009
  • Cell migration is one of the essential mechanisms responsible for complex biological processes. Intensive researches have begun to elucidate the mechanisms and search intriguing conditions for efficient control of cell migration. One general mechanism that is widely applicable for cells including Escherichia coli, amoebae and endothelial cell is chemotaxis. The single cell study for bacterial chemotaxis has an advantage over studies with the population of cells in providing a clearer observation of cell migration, which leads to more accurate assessments of chemotaxis. In this paper, we propose a three-dimensional model considering a single bacterium to study its chemotaxis. The semi-implicit Fourier spectral method is applied for high efficiency and numerical stability. The simulation results reveal rich dynamics of cell migration and provide quantitative assessments of bacterial chemotaxis with various chemoattractant gradient fields.

Peripheral Blood Leukocyte Chemotaxis Dysfunction in Rapidly Progressive Periodontitis (급성 진행성 치주염환자에서 백혈구 화학주성 기능부전에 관한 연구)

  • Jeong, Jong-Pyeong;Jeong, Hyeon-Ju;Jeong, Jin-Hyeong
    • The Journal of the Korean dental association
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    • v.21 no.10
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    • pp.805-812
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    • 1983
  • For the assessment of peripheral blood leukocyte chemotaxis dysfunction in rapidly progressive periodontitis, peripheral blood leukocyte of 13 patients were isolated, and tested by the method of blind well chamber technique which was recently developed by Park. Data analysis was performed from the speed of cell migration from the bottom of filter paper to the top for 18 minutes at the condition of chemo-attractant(Zymosan-activated serum). Eight of the 13 patients (62%) exhibited statistically significant inhibition of leukocyte chemotaxis, 4 patients revealed normal function and the other one patients showed elevated leukocyte chemotaxis. Four of the 8 patients in chemotaxis dysfunction showed significant inhibition of random migration and chemotaxis dysfunction both. Two of these 4 patients exhibited random migration impairment, elevation of C.D.I. and chemotaxis dysfunction. The results indicated that the progression of rapidly progressive periodontitis was influenced by the leukocyte chemotaxis dysfunction, and half of these dysfunction was associated with cell-defect of leukocyte.

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Inhibitory Effects of Cinnamic Acid Analogs on fMLP-Induced Chemotaxis of Rat Polymorphonuclear Leukocytes (흰쥐 다형핵백혈구의 fMLP로 유도한 유주현상에 대한 신나믹산 유사체의 억제효과)

  • Min, Kyung-Rak;Kim, Jin-Jun;Park, Sun-Gyoo;Lee, Jeong-Rai;Kang, Seh-Hoon;Kim, Young-Soo
    • YAKHAK HOEJI
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    • v.42 no.2
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    • pp.165-169
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    • 1998
  • Inhibitory effects of 16 cinnamic acid analogs on formyl-Met-Leu-Phe(fMLP)-induced chemotaxis of rat polymorphonuclear leukocytes were determined by using a microchemotaxis appa ratus. 3,4-Dlhydrocinnamic acid called as caffeic acid exhibited the highest inhibitory effect on the chemotaxis among cinnamic acid analogs tested in this study. Hydroxycinnamic acids exhibited stronger inhibitory effects on the chemotaxis than cinnnamic acid. Hydroxycinnamic acids with one hydroxy group at ortho, meta or para position exhibited similar inhibitory effects on the chemotaxis with corresponding methoxy cinnamic acids, but 3,4-dihydroxycinnamic acid did stronger inhibitory effects than 3,4-dimethoxycinnamic acid. 3,4-Dimethoxycinnamic acid exhibited weaker inhibitory effects on the chemotaxis than 1,2-dimethoxy-4-propenylbenzene and 3,4-dimethoxy cinnamonitrile with -CH=CHCN or -CH=$CHCH_3$, group instead of -CH=CHCOOH group. 4-Hydroxy cinnamic acid and 3,4-dihydroxycinnamic acid exhibited stronger exhibitory effects on the chemotaxis than 3-(4-hydroxyphenyl) propionic acid and 3,4-dihydroxyhydrocinnamic acid with -$CH_2CH_2$COOH group instead of -CH=CHCOOH group.

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ROBUST BOUNDARY CONTROL OF CHEMOTAXIS REACTION DIFFUSION SYSTEM

  • Ryu, Sang-Uk;Kang, Yong Han
    • Korean Journal of Mathematics
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    • v.16 no.4
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    • pp.457-470
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    • 2008
  • This paper is concerned with the robust boundary control of the chemotaxis reaction diffusion system. That is, we show that the existence of the saddle point for the robust control problem when the control and the disturbance are given by the boundary condition.

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NECESSARY CONDITIONS FOR OPTIMAL BOUNDARY CONTROL PROBLEM GOVERNED BY SOME CHEMOTAXIS EQUATIONS

  • Ryu, Sang-Uk
    • East Asian mathematical journal
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    • v.29 no.5
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    • pp.491-501
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    • 2013
  • This paper is concerned with the necessary conditions of the optimal boundary control for some chemotaxis equations. We obtain the existence and the necessary conditions of the optimal boundary control in the space $(H^1(0,T))^2$. Moreover, under some assumptions, we show the uniqueness of the optimal control.

INTERACTIVE DYNAMICS IN A BISTABLE ATTRACTION-REPULSION CHEMOTAXIS SYSTEM

  • Ham, YoonMee;Lee, Sang-Gu
    • Korean Journal of Mathematics
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    • v.24 no.2
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    • pp.215-233
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    • 2016
  • We consider a bistable attraction-repulsion chemotaxis system in one dimension. The study in this paper asserts that conditions for chemotactic coefficients for attraction and repulsion to show existence of stationary solutions and Hopf bifurcation in the interfacial problem as the bifurcation parameters vary are obtained analytically.

Assessing The Chemotaxis Of Spermatozoa By Microfludic Device (마이크로유체 장치를 이용한 정자 chemotaxis 평가)

  • Kim T.Y.;Oh T.Y.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.167-168
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    • 2006
  • Chemotaxis, or preferential motion due to presence of a chemical gradient, is an important factor in sperm fertilization of eggs in that it is the first interaction between sperm and egg. In the present study, we aim to quantify the possible chemoattractive role of the jelly coat. The chemotaxis of the sperm of sea urchin was demonstrated with the effective motility coefficient by a microfchannel made of polydimethysiloxane (PDMS). The relevance of these findings is that they provide insight on the first steps towards egg fertilization.

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