@article{1024,
abstract = {The history of auxin and cytokinin biology including the initial discoveries by father–son duo Charles Darwin and Francis Darwin (1880), and Gottlieb Haberlandt (1919) is a beautiful demonstration of unceasing continuity of research. Novel findings are integrated into existing hypotheses and models and deepen our understanding of biological principles. At the same time new questions are triggered and hand to hand with this new methodologies are developed to address these new challenges.},
author = {Hurny, Andrej and Benková, Eva},
issn = {10643745},
journal = {Auxins and Cytokinins in Plant Biology},
pages = {1 -- 29},
publisher = {Springer},
title = {{Methodological advances in auxin and cytokinin biology}},
doi = {10.1007/978-1-4939-6831-2_1},
volume = {1569},
year = {2017},
}
@article{664,
abstract = {Immune cells communicate using cytokine signals, but the quantitative rules of this communication aren't clear. In this issue of Immunity, Oyler-Yaniv et al. (2017) suggest that the distribution of a cytokine within a lymphatic organ is primarily governed by the local density of cells consuming it.},
author = {Assen, Frank P and Sixt, Michael K},
issn = {10747613},
journal = {Immunity},
number = {4},
pages = {519 -- 520},
publisher = {Cell Press},
title = {{The dynamic cytokine niche}},
doi = {10.1016/j.immuni.2017.04.006},
volume = {46},
year = {2017},
}
@article{1008,
abstract = {Feedback loops in biological networks, among others, enable differentiation and cell cycle progression, and increase robustness in signal transduction. In natural networks, feedback loops are often complex and intertwined, making it challenging to identify which loops are mainly responsible for an observed behavior. However, minimal synthetic replicas could allow for such identification. Here, we engineered a synthetic permease-inducer-repressor system in Saccharomyces cerevisiae to analyze if a transport-mediated positive feedback loop could be a core mechanism for the switch-like behavior in the regulation of metabolic gene networks such as the S. cerevisiae GAL system or the Escherichia coli lac operon. We characterized the synthetic circuit using deterministic and stochastic mathematical models. Similar to its natural counterparts, our synthetic system shows bistable and hysteretic behavior, and the inducer concentration range for bistability as well as the switching rates between the two stable states depend on the repressor concentration. Our results indicate that a generic permease–inducer–repressor circuit with a single feedback loop is sufficient to explain the experimentally observed bistable behavior of the natural systems. We anticipate that the approach of reimplementing natural systems with orthogonal parts to identify crucial network components is applicable to other natural systems such as signaling pathways.},
author = {Gnügge, Robert and Dharmarajan, Lekshmi and Lang, Moritz and Stelling, Jörg},
journal = {ACS Synthetic Biology},
number = {10},
pages = {1098 -- 1107},
publisher = {American Chemical Society},
title = {{An orthogonal permease–inducer–repressor feedback loop shows bistability}},
doi = {10.1021/acssynbio.6b00013},
volume = {5},
year = {2016},
}
@article{1081,
abstract = {The asymmetric localization of proteins in the plasma membrane domains of eukaryotic cells is a fundamental manifestation of cell polarity that is central to multicellular organization and developmental patterning. In plants, the mechanisms underlying the polar localization of cargo proteins are still largely unknown and appear to be fundamentally distinct from those operating in mammals. Here, we present a systematic, quantitative comparative analysis of the polar delivery and subcellular localization of proteins that characterize distinct polar plasma membrane domains in plant cells. The combination of microscopic analyses and computational modeling revealed a mechanistic framework common to diverse polar cargos and underlying the establishment and maintenance of apical, basal, and lateral polar domains in plant cells. This mechanism depends on the polar secretion, constitutive endocytic recycling, and restricted lateral diffusion of cargos within the plasma membrane. Moreover, our observations suggest that polar cargo distribution involves the individual protein potential to form clusters within the plasma membrane and interact with the extracellular matrix. Our observations provide insights into the shared cellular mechanisms of polar cargo delivery and polarity maintenance in plant cells.},
author = {Łangowski, Łukasz and Wabnik, Krzysztof T and Li, Hongjiang and Vanneste, Steffen and Naramoto, Satoshi and Tanaka, Hirokazu and Friml, Jirí},
journal = {Cell Discovery},
publisher = {Nature Publishing Group},
title = {{Cellular mechanisms for cargo delivery and polarity maintenance at different polar domains in plant cells}},
doi = {10.1038/celldisc.2016.18},
volume = {2},
year = {2016},
}
@inproceedings{1082,
abstract = {In many applications, it is desirable to extract only the relevant aspects of data. A principled way to do this is the information bottleneck (IB) method, where one seeks a code that maximises information about a relevance variable, Y, while constraining the information encoded about the original data, X. Unfortunately however, the IB method is computationally demanding when data are high-dimensional and/or non-gaussian. Here we propose an approximate variational scheme for maximising a lower bound on the IB objective, analogous to variational EM. Using this method, we derive an IB algorithm to recover features that are both relevant and sparse. Finally, we demonstrate how kernelised versions of the algorithm can be used to address a broad range of problems with non-linear relation between X and Y.},
author = {Chalk, Matthew J and Marre, Olivier and Tkacik, Gasper},
location = {Barcelona, Spain},
pages = {1965--1973},
publisher = {Neural Information Processing Systems},
title = {{Relevant sparse codes with variational information bottleneck}},
volume = {29},
year = {2016},
}
@article{1083,
abstract = { Cholecystokinin-expressing interneurons (CCK-INs) mediate behavior state-dependent inhibition in cortical circuits and themselves receive strong GABAergic input. However, it remains unclear to what extent GABABreceptors (GABABRs) contribute to their inhibitory control. Using immunoelectron microscopy, we found that CCK-INs in the rat hippocampus possessed high levels of dendritic GABABRs and KCTD12 auxiliary proteins, whereas postsynaptic effector Kir3 channels were present at lower levels. Consistently, whole-cell recordings revealed slow GABABR-mediated inhibitory postsynaptic currents (IPSCs) in most CCK-INs. In spite of the higher surface density of GABABRs in CCK-INs than in CA1 principal cells, the amplitudes of IPSCs were comparable, suggesting that the expression of Kir3 channels is the limiting factor for the GABABR currents in these INs. Morphological analysis showed that CCK-INs were diverse, comprising perisomatic-targeting basket cells (BCs), as well as dendrite-targeting (DT) interneurons, including a previously undescribed DT type. GABABR-mediated IPSCs in CCK-INs were large in BCs, but small in DT subtypes. In response to prolonged activation, GABABR-mediated currents displayed strong desensitization, which was absent in KCTD12-deficient mice. This study highlights that GABABRs differentially control CCK-IN subtypes, and the kinetics and desensitization of GABABR-mediated currents are modulated by KCTD12 proteins. },
author = {Booker, Sam and Althof, Daniel and Gross, Anna and Loreth, Desiree and Müller, Johanna and Unger, Andreas and Fakler, Bernd and Varro, Andrea and Watanabe, Masahiko and Gassmann, Martin and Bettler, Bernhard and Shigemoto, Ryuichi and Vida, Imre and Kulik, Ákos},
journal = {Cerebral Cortex},
number = {3},
pages = {2318 -- 2334},
publisher = {Oxford University Press},
title = {{KCTD12 auxiliary proteins modulate kinetics of GABAB receptor-mediated inhibition in Cholecystokinin-containing interneurons}},
doi = {10.1093/cercor/bhw090},
volume = {27},
year = {2016},
}
@inproceedings{1090,
abstract = { While weighted automata provide a natural framework to express quantitative properties, many basic properties like average response time cannot be expressed with weighted automata. Nested weighted automata extend weighted automata and consist of a master automaton and a set of slave automata that are invoked by the master automaton. Nested weighted automata are strictly more expressive than weighted automata (e.g., average response time can be expressed with nested weighted automata), but the basic decision questions have higher complexity (e.g., for deterministic automata, the emptiness question for nested weighted automata is PSPACE-hard, whereas the corresponding complexity for weighted automata is PTIME). We consider a natural subclass of nested weighted automata where at any point at most a bounded number k of slave automata can be active. We focus on automata whose master value function is the limit average. We show that these nested weighted automata with bounded width are strictly more expressive than weighted automata (e.g., average response time with no overlapping requests can be expressed with bound k=1, but not with non-nested weighted automata). We show that the complexity of the basic decision problems (i.e., emptiness and universality) for the subclass with k constant matches the complexity for weighted automata. Moreover, when k is part of the input given in unary we establish PSPACE-completeness.},
author = {Chatterjee, Krishnendu and Henzinger, Thomas A and Otop, Jan},
location = {Krakow; Poland},
publisher = {Schloss Dagstuhl - Leibniz-Zentrum für Informatik},
title = {{Nested weighted limit-average automata of bounded width}},
doi = {10.4230/LIPIcs.MFCS.2016.24},
volume = {58},
year = {2016},
}
@inproceedings{1068,
abstract = {Games on graphs provide the appropriate framework to study several central problems in computer science, such as verification and synthesis of reactive systems. One of the most basic objectives for games on graphs is the liveness (or Büchi) objective that given a target set of vertices requires that some vertex in the target set is visited infinitely often. We study generalized Büchi objectives (i.e., conjunction of liveness objectives), and implications between two generalized Büchi objectives (known as GR(1) objectives), that arise in numerous applications in computer-aided verification. We present improved algorithms and conditional super-linear lower bounds based on widely believed assumptions about the complexity of (A1) combinatorial Boolean matrix multiplication and (A2) CNF-SAT. We consider graph games with n vertices, m edges, and generalized Büchi objectives with k conjunctions. First, we present an algorithm with running time O(k*n^2), improving the previously known O(k*n*m) and O(k^2*n^2) worst-case bounds. Our algorithm is optimal for dense graphs under (A1). Second, we show that the basic algorithm for the problem is optimal for sparse graphs when the target sets have constant size under (A2). Finally, we consider GR(1) objectives, with k_1 conjunctions in the antecedent and k_2 conjunctions in the consequent, and present an O(k_1 k_2 n^{2.5})-time algorithm, improving the previously known O(k_1*k_2*n*m)-time algorithm for m > n^{1.5}. },
author = {Chatterjee, Krishnendu and Dvorák, Wolfgang and Henzinger, Monika and Loitzenbauer, Veronika},
location = {Krakow, Poland},
publisher = {Schloss Dagstuhl - Leibniz-Zentrum für Informatik},
title = {{Conditionally optimal algorithms for generalized Büchi Games}},
doi = {10.4230/LIPIcs.MFCS.2016.25},
volume = {58},
year = {2016},
}
@inproceedings{1069,
abstract = {The Continuous Skolem Problem asks whether a real-valued function satisfying a linear differen-
tial equation has a zero in a given interval of real numbers. This is a fundamental reachability
problem for continuous linear dynamical systems, such as linear hybrid automata and continuous-
time Markov chains. Decidability of the problem is currently open – indeed decidability is open
even for the sub-problem in which a zero is sought in a bounded interval. In this paper we show
decidability of the bounded problem subject to Schanuel’s Conjecture, a unifying conjecture in
transcendental number theory. We furthermore analyse the unbounded problem in terms of the
frequencies of the differential equation, that is, the imaginary parts of the characteristic roots.
We show that the unbounded problem can be reduced to the bounded problem if there is at most
one rationally linearly independent frequency, or if there are two rationally linearly independent
frequencies and all characteristic roots are simple. We complete the picture by showing that de-
cidability of the unbounded problem in the case of two (or more) rationally linearly independent
frequencies would entail a major new effectiveness result in Diophantine approximation, namely
computability of the Diophantine-approximation types of all real algebraic numbers.},
author = {Chonev, Ventsislav K and Ouaknine, Joël and Worrell, James},
location = {Rome, Italy},
publisher = {Schloss Dagstuhl- Leibniz-Zentrum fur Informatik},
title = {{On the skolem problem for continuous linear dynamical systems}},
doi = {10.4230/LIPIcs.ICALP.2016.100},
volume = {55},
year = {2016},
}
@inproceedings{1070,
abstract = {We present a logic that extends CTL (Computation Tree Logic) with operators that express synchronization properties. A property is synchronized in a system if it holds in all paths of a certain length. The new logic is obtained by using the same path quantifiers and temporal operators as in CTL, but allowing a different order of the quantifiers. This small syntactic variation induces a logic that can express non-regular properties for which known extensions of MSO with equality of path length are undecidable. We show that our variant of CTL is decidable and that the model-checking problem is in Delta_3^P = P^{NP^NP}, and is DP-hard. We analogously consider quantifier exchange in extensions of CTL, and we present operators defined using basic operators of CTL* that express the occurrence of infinitely many synchronization points. We show that the model-checking problem remains in Delta_3^P. The distinguishing power of CTL and of our new logic coincide if the Next operator is allowed in the logics, thus the classical bisimulation quotient can be used for state-space reduction before model checking. },
author = {Chatterjee, Krishnendu and Doyen, Laurent},
location = {Rome, Italy},
publisher = {Schloss Dagstuhl- Leibniz-Zentrum fur Informatik},
title = {{Computation tree logic for synchronization properties}},
doi = {10.4230/LIPIcs.ICALP.2016.98},
volume = {55},
year = {2016},
}