Activation of the Na+/K+-ATPase by insulin and glucose as a putative negative feedback mechanism in pancreatic beta-cells

2008 ◽  
Vol 457 (6) ◽  
pp. 1351-1360 ◽  
Author(s):  
M. Düfer ◽  
D. Haspel ◽  
P. Krippeit-Drews ◽  
L. Aguilar-Bryan ◽  
J. Bryan ◽  
...  
2013 ◽  
Vol 10 (81) ◽  
pp. 20121009 ◽  
Author(s):  
Tomer J. Czaczkes ◽  
Christoph Grüter ◽  
Francis L. W. Ratnieks

Crowding in human transport networks reduces efficiency. Efficiency can be increased by appropriate control mechanisms, which are often imposed externally. Ant colonies also have distribution networks to feeding sites outside the nest and can experience crowding. However, ants do not have external controllers or leaders. Here, we report a self-organized negative feedback mechanism, based on local information, which downregulates the production of recruitment signals in crowded parts of a network by Lasius niger ants. We controlled crowding by manipulating trail width and the number of ants on a trail, and observed a 5.6-fold reduction in the number of ants depositing trail pheromone from least to most crowded conditions. We also simulated crowding by placing glass beads covered in nest-mate cuticular hydrocarbons on the trail. After 10 bead encounters over 20 cm, forager ants were 45 per cent less likely to deposit pheromone. The mechanism of negative feedback reported here is unusual in that it acts by downregulating the production of a positive feedback signal, rather than by direct inhibition or the production of an inhibitory signal.


2006 ◽  
Vol 20 (4) ◽  
Author(s):  
Damian G Romero ◽  
Maria W Plonczynski ◽  
Licy L Yanes ◽  
Tanganika R Washington ◽  
Gina Covington ◽  
...  

Blood ◽  
2013 ◽  
Vol 121 (19) ◽  
pp. 3843-3854 ◽  
Author(s):  
Antonella Teramo ◽  
Cristina Gattazzo ◽  
Francesca Passeri ◽  
Albana Lico ◽  
Giulia Tasca ◽  
...  

Key PointsIn T-LGLL, autologous LGL-depleted PBMCs release high levels of IL-6 contributing to the constitutive STAT3 activation in leukemic LGL. Leukemic LGLs show SOCS3 down-modulation, which is responsible for lack of the negative feedback mechanism controlling STAT3 activation.


1979 ◽  
Vol 55 (6) ◽  
pp. 776-786
Author(s):  
Masatomo MORI ◽  
Kihachi OHSHIMA ◽  
Sakae MARUTA ◽  
Hitoshi FUKUDA ◽  
Yohnosuke SHIMOMURA ◽  
...  

2003 ◽  
Vol 172 (1) ◽  
pp. 170-177 ◽  
Author(s):  
Shi-Chuen Miaw ◽  
Bok Yun Kang ◽  
Ian Alexander White ◽  
I-Cheng Ho

2020 ◽  
Author(s):  
Xiaomin Fang ◽  
Albert Galy ◽  
Yibo Yang ◽  
Weilin Zhang ◽  
Chengcheng Ye ◽  
...  

<p>The CO<sub>2</sub> degassing by plate tectonic process has long been thought to be balanced by weathering of silicate rocks on continents, keeping the Earth a relative stable global carbon cycle and temperature suitable for life creation, survival and evolution. The uplift of the Tibetan Plateau (TP) is hypothesized to enhance erosion and silicate weathering and organic carbon burial, thus cool the global temperature. However, the imbalance resulting from accelerated CO<sub>2</sub> consumption by uplift of the TP and a relatively stable CO<sub>2</sub> input from volcanic degassing during the Cenozoic should have depleted atmospheric CO<sub>2</sub> within a few million years; therefore, a negative feedback mechanism must have stabilised the carbon cycle. Here, we present the first almost complete Paleogene silicate weathering intensity (SWI) records from continental rocks in the northern TP, based on detailed volcanic ash and paleomagnetic dating of two continuous Cenozoic sections in the Xining and Qaidam Basin in NW China. They show that the Paleogene silicate weathering in this tectonically inactive area was modulated by global temperature. These findings suggest that Paleogene global cooling was also strongly influenced by the temperature feedback mechanism that regulated silicate weathering rates and hydrological cycles and maintained a nearly stable carbon cycle. It acted as a negative feedback through decreasing CO<sub>2</sub> consumption resulting from the lower SWI and the kinetic limitations in tectonically inactive areas that followed the global cooling. This means that the enhanced erosion and silicate weathering by the uplift of the south and central Tibetan Plateau, thus accelerated CO<sub>2</sub> consumption, must be compensated by reducing CO<sub>2</sub> consumption of the rest vast continents through their reduced silicate weathering from cooling.</p>


Sign in / Sign up

Export Citation Format

Share Document