Journal of mechanochemistry & cell motility最新文献

{"title":"Actin, myosin and cofactor from motile cells.","authors":"T D Pollard","doi":"","DOIUrl":"","url":null,"abstract":"","PeriodicalId":76011,"journal":{"name":"Journal of mechanochemistry & cell motility","volume":"4 1","pages":"15-30"},"PeriodicalIF":0.0,"publicationDate":"1977-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11375186","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Immobilization of actin and myosin.","authors":"B F Poglazov,&nbsp;G G Ivanov,&nbsp;A L Metlina","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Using glutaric dialdehyde, the muscle proteins myosin, actin, actomyosin and heavy meromyosin subfragment-1 (S-1) have been immobilized on capron fibers. The ATPase activity of myosin and its capability to interact with actin have been preserved whereas the ATPase activity of its subfragment decreased significnatly. Immobilization on capron fibers changes the pH dependence of the ATPase activity of myosin and of S-1 shifting the maximum towards the acid zone (pH 5.5) and increases the thermal stability of the enzyme. Calcium ions produce a stimulatory effect on ATPase; Mg2+ions yield no effect on myosin and S-1 but enhance the activity in the case of immobilized actomyosin though to a lesser degree than the ions of Ca2+. Immobilized actin retains its ability to form actomyosin complex.</p>","PeriodicalId":76011,"journal":{"name":"Journal of mechanochemistry & cell motility","volume":"4 1","pages":"87-99"},"PeriodicalIF":0.0,"publicationDate":"1977-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11261117","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Platelet contractile force in relation to streaming in human thrombosthenin solutions.","authors":"I Cohen","doi":"","DOIUrl":"","url":null,"abstract":"","PeriodicalId":76011,"journal":{"name":"Journal of mechanochemistry & cell motility","volume":"4 1","pages":"31-5"},"PeriodicalIF":0.0,"publicationDate":"1977-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11776412","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Amoeboid movement in human leucocytes: basic mechanisms, cytobiological and clinical significance.","authors":"B Norberg,&nbsp;U Bandmann,&nbsp;L Rydgren","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The present paper is an analytical review of the information available on amoeboid movement in human leucocytes. The reported evidence suggests that leucocyte locomotion is due to pressure developed in the cell cortex in the middle and posterior parts of the moving cell, that 4 nm fibrils may provide at least part of the ultrastructural basis of locomotion, that actin-like and myosin-like proteins may be involved in the mechanism of movement and that ATP may serve as an energy source. Leucocyte motility appears to be governed mainly by factors produced in the external medium. Neutrophil chemotaxis is the most antitubulin-susceptible cell mechanism known; from this observation an essential role of microtubule redistribution in chemotaxis is inferred. In contrast, the random movement of neutrophils is not appreciably affected by antimitotic concentrations of antitubulins. Amoeboid movement seems to be an important mechanism in the short-distance locomotion and immunological functions of leucocytes.</p>","PeriodicalId":76011,"journal":{"name":"Journal of mechanochemistry & cell motility","volume":"4 1","pages":"37-53"},"PeriodicalIF":0.0,"publicationDate":"1977-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11589985","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dynamic characteristics of F-actin and thin filaments in vivo and in vitro.","authors":"F Oosawa,&nbsp;Y Maeda,&nbsp;S Fujime,&nbsp;S Ishiwata,&nbsp;T Yanagida,&nbsp;M Taniguchi","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Measurements of birefringence, ultraviolet dichorism and quasielastic light scattering were carried out on F-actin in solution and on the thin filaments of glycerinated myofibrils. The birefringence of the I-bands of myofibrils was of the same order of magnitude as that of F-actin or the F-actin-tropomyosin-troponin complex oriented in vitro at the same concentration. The ultraviolet dichroism spectrum of the I-bands was very similar to that of F-actin or the F-actin complex in vitro, which is due to orientation of bound ADP and tryptophan residues in F-actin. Quasielastic light scattering measurements, electronmicroscopic observations and the analyses of the electro-optic effect of the I-bands suggested approximately the same flexibility for F-actin in vitro and for the thin filaments in vivo. These optical measurements which were made under various conditions provide evidence for a conformational change induced by calcium ions in F-actin both in vivo and in vitro. This conformational change was found to be amplified by the interaction of F-actin with myosin. This is a brief review of our investigation on the dynamics of F-actin and the thin filament in vivo and in vitro by optical methods.</p>","PeriodicalId":76011,"journal":{"name":"Journal of mechanochemistry & cell motility","volume":"4 1","pages":"63-78"},"PeriodicalIF":0.0,"publicationDate":"1977-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11776413","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A continuum theory of Allen's frontal contraction model of amoeboid pseudopodium extension.","authors":"G M Odell","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>A continuum theory is proposed for the chemically controlled cytoplasmic streaming observed in pseudopodium extension in Chaos Carolinensis. Amoeboid cytoplasm is assumed to consist of submicroscopic contractile fibers bathed by viscous fluid. The fiber constituent models the actin-like and myosin-like contractile machinery known to be present in Chaos Carolinensis cytoplasm. A \"trigger chemical\", produced at the pseudopodium tip, moves by diffusion in, and convection by, the viscous fluid, and causes the contractile fibers to contract in their own length. The contracting fibers, attached at the tip and running continuously back toward the amoeba cell body, pull the fluid constituent of the cytoplasm forward and ultimately crosslink to form the outer gel tube of the advancing pseudopodium. That is, streaming cytoplasm is modeled as a two constituent porous medium, with the fluid constituent free to flow through a porous matrix of oriented (contractile fiber) rods, while the matrix of rods itself moves as the fibers contract, with fiber contraction controlled by a trigger chemical born by the fluid constituent. According to this theory, in the region behind the advancing pseudopodium tip, the contractile fiber rods move forward toward the tip faster than the fluid constituent. The hydrostatic pressure in the fluid therefore increases from the cell body toward the tip (Just the opposite from flow driven by pressure excess generated in the cell body). The excess of hydrostatic pressure above ambient built up at the tip provides the force to roll out the advancing pseudopodium tip. The cell membrane plays no active mechanical role. The mathematical transcription makes a precise theory of R. D. Allen's \"frontal (or fountain zone) contraction model\". The general system of coupled, non-linear, partial differential equations is solved for its simplest non-trivial special case, that of a steady-state motion, as seen from a coordinate system attached to the advancing tip. Solutions exist, and, for each distinct forward speed (which is left to the discretion of the amoeba) the solution is unique. The theory predicts both upper and lower bounds for possible pseudopodium lengths.</p>","PeriodicalId":76011,"journal":{"name":"Journal of mechanochemistry & cell motility","volume":"4 1","pages":"1-13"},"PeriodicalIF":0.0,"publicationDate":"1977-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11953852","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The efficiency of mechano-chemical cycles and the mechano-chemical availability function.","authors":"M V Sussman","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>This paper deals with elementary thermodynamic considerations applicable to mechano-chemical cycles. It shall review concepts about the efficiency of these cycles and then suggest an extension of the concept of the Availability Function to be called the Mechano-Chemical Availability Function.</p>","PeriodicalId":76011,"journal":{"name":"Journal of mechanochemistry & cell motility","volume":"4 1","pages":"55-61"},"PeriodicalIF":0.0,"publicationDate":"1977-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11953853","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dielectric dispersion of actin.","authors":"T J Herbert,&nbsp;J K Weltman,&nbsp;A R Frackelton,&nbsp;R M Dowben","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The dielectric dispersion of G-actin was 7 X 10(6) Hz, and the low frequency reduced dielectric increment 0.99 +/- 0.15 ml/mg. The dielectric increment of F-actin in the range 10(5) to 10(8) Hz was very low, about 0.3.</p>","PeriodicalId":76011,"journal":{"name":"Journal of mechanochemistry & cell motility","volume":"4 1","pages":"79-85"},"PeriodicalIF":0.0,"publicationDate":"1977-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11776414","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Polymerization polarity of actin.","authors":"T Hayashi,&nbsp;W Ip","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The actin polymer, like the thin filaments of muscle, is known to be polarized as demonstrated by the well known \"HMM decoration\" technique to give a \"herringbone\" pattern pointing in one direction. The question \"Does polymer formation proceed unidirectionally, or bidirectionally?\" was raised and tested experimentally. Short fragments of actin polymers were prepared, fully decorated with HMM and these decorated fragments were used as initiation centers for further actin polymerization without HMM. The resultant polymers showing both decorated and undecorated portions were examined and found to consist of a large majority of \"spears\" i.e., the added undecorated polymer extended in the direction opposite to that direction pointed by the \"herringbone\" pattern. However, a few cases of polymers indicating the opposite direction of polymerization were also found. Analysis leads to the conclusion that actin polymerization is unidirectional, although further experimentation is necessary to establish this completely.</p>","PeriodicalId":76011,"journal":{"name":"Journal of mechanochemistry & cell motility","volume":"3 3","pages":"163-9"},"PeriodicalIF":0.0,"publicationDate":"1976-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12115637","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Conformational changes induced in plasmodium actin polymer by Ca2+ in the presence of muscle native tropomysin.","authors":"H Tanaka,&nbsp;S Hatano","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The flexible polymer of plasmodium actin (Mg-polymer) combines with muscle native tropomyosin up to a weight ratio of actin: tropomyosin:troponin = 6:1:1. Mg-polymer which combined with muscle native tropomyosin undergoes a conformational change when the Ca2+ concentration of the solution is decreased by adding 0.5 mM ethylene glycol bis(beta-aminoethylether)-N,N'-tetraacetic acid (EGTA): the viscosity of the solution increases by 50% and its ATPase activity decreases to about 20% of the original value, which suggests that the structure of Mg-polymer becomes more rigid. This change is reversible with respect to the Ca2+ concentration in the solution. The threshold concentration of Ca2+ for the conformational change is about 10(-6) M. The possible role of this transformation in vivo is discussed.</p>","PeriodicalId":76011,"journal":{"name":"Journal of mechanochemistry & cell motility","volume":"3 3","pages":"195-200"},"PeriodicalIF":0.0,"publicationDate":"1976-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12115639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}