scholarly journals Inorganic matter can act life-like active transport

Author(s):  
Yan Zu ◽  
Luoran Shang
Author(s):  
G. Zampighi ◽  
M. Kreman

The plasma membranes of most animal cells contain transport proteins which function to provide passageways for the transported species across essentially impermeable lipid bilayers. The channel is a passive transport system which allows the movement of ions and low molecular weight molecules along their concentration gradients. The pump is an active transport system and can translocate cations against their natural concentration gradients. The actions and interplay of these two kinds of transport proteins control crucial cell functions such as active transport, excitability and cell communication. In this paper, we will describe and compare several features of the molecular organization of pumps and channels. As an example of an active transport system, we will discuss the structure of the sodium and potassium ion-activated triphosphatase [(Na+ +K+)-ATPase] and as an example of a passive transport system, the communicating channel of gap junctions and lens junctions.


Derrida Today ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 72-94
Author(s):  
Bernard Stiegler

These lectures outline the project of a general organology, which is to say an account of life when it is no longer just biological but technical, or when it involves not just organic matter but organized inorganic matter. This organology is also shown to require a modified Simondonian account of the shift from vital individuation to a three-stranded process of psychic, collective and technical individuation. Furthermore, such an approach involves extending the Derridean reading of Socrates's discussion of writing as a pharmakon, so that it becomes a more general account of the pharmacological character of retention and protention. By going back to Leroi-Gourhan, we can recognize that this also means pursuing the history of retentional modifications unfolding in the course of the history of what, with Lotka, can also be called exosomatization. It is thus a question of how exteriorization can, today, in an epoch when it becomes digital, and in an epoch that produces vast amounts of entropy at the thermodynamic, biological and noetic levels, still possibly produce new forms of interiorization, that is, new forms of thought, care and desire, amounting to so many chances to struggle against the planetary-scale pharmacological crisis with which we are currently afflicted.


2016 ◽  
Vol 136 (9) ◽  
pp. 384-389
Author(s):  
Kazuya Fujimoto ◽  
Hirofumi Shintaku ◽  
Hidetoshi Kotera ◽  
Ryuji Yokokawa

1982 ◽  
Vol 242 (3) ◽  
pp. R380-R389 ◽  
Author(s):  
J. K. Foskett ◽  
T. E. Machen ◽  
H. A. Bern

Effects of prolactin on transport properties of opercular membranes from seawater-adapted tilapia, Sarotherodon mossambicus, have been examined. These membranes are high conductance (average Gt approximately 4 mS.cm-2) tissues with short-circuit currents (I) equal to net chloride secretion. Despite high Gt, nonlinear current-voltage relationships suggest that opercular membranes cannot be classified as "leaky" tissues. Variability among membranes is reflected in a linear relationship between I and Gt with a slope equal to 26 mV and the zero-current Gt intercept equal to 0.45 mS.cm-2. Prolactin injections decrease I and Gt in a dose-dependent manner. Phosphodiesterase inhibition, without effect on I in untreated fish, often partially reverses these prolactin effects. Gt-I data from prolactin-treated fish yield a slope of 18 mV and a Gt intercept of 0.10 mS.cm-2. The effects of prolactin are discussed in terms of conventional equivalent circuit analysis. Discrepancies between predictions based on this model and the actual data indicate that an alternative interpretation, based on a heterogeneous cell population, is more accurate. Analysis of this circuit suggests that the ratio of paracellular to active transport pathway conductances associated with chloride cells is constant and that differences in Gt and I are due to parallel changes in these conductances. Prolactin may effectively "remove" chloride cells from these membranes as well as inhibit (reversible by elevated cellular cAMP levels) active transport pathway conductance of remaining cells.


2002 ◽  
Vol 30 (5) ◽  
pp. 498-504 ◽  
Author(s):  
Yoshihiro Kawabata ◽  
Shigeru Furuta ◽  
Yutaka Shinozaki ◽  
Tadashi Kurimoto ◽  
Ryuichiro Nishigaki

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