Annila A.,FI |
Annila A.,Institute of Biotechnology |
Salthe S.,Binghamton University State University of New York
Journal of Non-Equilibrium Thermodynamics | Year: 2010
The theory of evolution by natural selection is herein subsumed by the 2nd law of thermodynamics. The mathematical form of evolutionary theory is based on a re-examination of the probability concept that underlies statistical physics. Probability regarded as physical must include, in addition to isoenergic combinatorial configurations, also energy in conditional circumstances. Consequently, entropy as an additive logarithmic probability measure is found to be a function of the free energy, and the process toward the maximum entropy state is found equivalent to evolution toward the free energy minimum in accordance with the basic maxim of chemical thermodynamics. The principle of increasing entropy when given as an equation of motion reveals that expansion, proliferation, differentiation, diversification, and catalysis are all ways for a system to evolve toward the stationary state in its respective surroundings. Intriguingly, the equation of evolution cannot be solved when there remain degrees of freedom to consume the free energy, and hence evolutionary trajectories of a non-Hamiltonian system remain intractable. Finally, when to-and-from flows of energy are balanced between a system and its surroundings, the system is at the Lyapunov-stable stationary state. The principle of maximal energy dispersal, equivalent to the maximal rate of entropy production, gives rise to the ubiquitous characteristics, conventions, and regularities found in nature, where thermodynamics makes no demarcation line between animate and inanimate. © 2010 de Gruyter.
Lucking R.,Field Museum |
Niezgoda C.,Field Museum |
Huhtinen S.,FI |
McCaffrey J.,Field Museum |
Lumbsch H.T.,Field Museum
Bryologist | Year: 2011
The new foliicolous lichen Coccocarpia melloniorum Lcking from the Philippines is described and illustrated. It is morphologically similar to C. epiphylla but differs in the formation of disc-shaped isidia and dark rhizines. The species was discovered as part of a type digitization project through the Global Plant Initiative (GPI), as part of a syntype collection of Leptogium phyllogenum f. subsinuatum Vain. © 2011 The American Bryological and Lichenological Society, Inc.
Brosche M.,FI |
Merilo E.,University of Helsinki |
Mayer F.,FI |
Mayer F.,University of Helsinki |
And 8 more authors.
Plant, Cell and Environment | Year: 2010
Genetic variation between naturally occurring populations provides a unique source to unravel the complex mechanisms of stress tolerance. Here, we have analysed O3 sensitivity of 93 natural Arabidopsis thaliana accessions together with five O3-sensitive mutants to acute O3 exposure. The variation in O3 sensitivity among the natural accessions was much higher than among the O3-sensitive mutants and corresponding wild types. A subset of nine accessions with major variation in their O3 responses was studied in more detail. Among the traits assayed, stomatal conductance (gst) was an important factor determining O3 sensitivity of the selected accessions. The most O3-sensitive accession, Cvi-0, had constitutively high gst, leading to high initial O3 uptake rate and dose received during the first 30 min of exposure. Analyzing O3-induced changes in stress hormone concentrations indicated that jasmonate (JA) concentration was also positively correlated with leaf damage. Quantitative trait loci (QTL) mapping in a Col-0 × Cvi-0 recombinant inbred line (RIL) population identified three QTLs for O3 sensitivity, and one for high water loss of Cvi-0. The major O3 QTL mapped to the same position as the water loss QTL further supporting the role of stomata in regulating O3 entry and damage. © 2010 Blackwell Publishing Ltd.
Viitanen T.,FI |
Ruusuvuori E.,FI |
Kaila K.,FI |
Kaila K.,University of Helsinki |
Journal of Physiology | Year: 2010
GABAergic excitatory [K+]o transients can be readily evoked in the mature rat hippocampus by intense activation of GABAA receptors (GABAARs). Here we show that these [K+]o responses induced by high-frequency stimulation or GABAA agonist application are generated by the neuronal K+-Cl- cotransporter KCC2 and that the transporter-mediated KCl extrusion is critically dependent on the bicarbonate-driven accumulation of Cl- in pyramidal neurons. The mechanism underlying GABAergic [K+]o transients was studied in CA1 stratum pyramidale using intracellular sharp microelectrodes and extracellular ion-sensitive microelectrodes. The evoked [K+]o transients, as well as the associated afterdischarges, were strongly suppressed by 0.5-1 mm furosemide, a KCl cotransport inhibitor. Importantly, the GABAAR-mediated intrapyramidal accumulation of Cl-, as measured by monitoring the reversal potential of fused IPSPs, was unaffected by the drug. It was further confirmed that the reduction in the [K+]o transients was not due to effects of furosemide on the Na+-dependent K+-Cl- cotransporter NKCC1 or on intraneuronal carbonic anhydrase activity. Blocking potassium channels by Ba2+ enhanced [K+]o transients whereas pyramidal cell depolarizations were attenuated in further agreement with a lack of contribution by channel-mediated K+ efflux. The key role of the GABAAR channel-mediated anion fluxes in the generation of the [K+]o transients was examined in experiments where bicarbonate was replaced with formate. This anion substitution had no significant effect on the rate of Cl- accumulation, [K+]o response or afterdischarges. Our findings reveal a novel excitatory mode of action of KCC2 that can have substantial implications for the role of GABAergic transmission during ictal epileptiform activity. © 2010 The Authors. Journal compilation © 2010 The Physiological Society.
Kumar N.,University of Turku |
Leino E.,University of Turku |
Maki-Arvela P.,University of Turku |
Aho A.,University of Turku |
And 8 more authors.
Microporous and Mesoporous Materials | Year: 2012
Synthesis of solid base Ce-H-MCM-41, Ce-Si-MCM-41, Cs-MCM-41, K-MCM-41 mesoporous materials and Na-ZSM-12, Cs-ZSM-12 microporous zeolites were carried out by means of evaporation impregnation and ion-exchange methods. The solid base catalysts were characterized using X-ray powder diffraction, scanning electron microscope, nitrogen adsorption, FTIR of pyridine and temperature programmed desorption of CO 2. The H-ZSM-12, Cs-ZSM-12 zeolite, H-MCM-41, Ce-H-MCM-41 and Ce-Si-MCM-41 mesoporous catalysts were studied for the synthesis of diethyl carbonate starting from ethanol and carbon dioxide, using butylene oxide as the dehydrating agent. Catalyst testing for the synthesis of diethyl carbonate was carried out at 170°C and 4.5 MPa of initial CO 2 pressure. 16 wt.% Ce-H-MCM-41 mesoporous material exhibited higher amount of weak, medium and strong basic sites than that of 32 wt.% Ce-Si-MCM-41. The presence of weak and strong basic sites was observed in the microporous 2 wt.% Cs-ZSM-12 catalyst. Diethyl carbonate formation was observed over Ce-H-MCM-41 and Ce-Si-MCM-41 mesoporous materials. Amount of basic sites and its strength influenced the synthesis of diethyl carbonate over the mesoporous materials. © 2011 Elsevier Inc. All rights reserved.