Data Descriptor: A genome-scale RNAi screen for genetic interactors of the dynein co-factor nud-2 in Caenorhabditis elegans

Cytoplasmic dynein 1 (dynein) is the predominant microtubule minus end-directed motor in animals and participates in a wide range of cellular processes, including membrane trafficking, nuclear migration, and cell division. Dynein's functional diversity depends on co-factors that regulate its subcellular localization, interaction with cargo, and motor activity. The ubiquitous co-factor nuclear distribution gene E (NudE) is implicated in many of dynein's functions, and mutations in NudE cause the brain developmental disease microcephaly. To identify genetic interactors of the Caenorhabditis elegans NudE homolog nud-2, we performed a genome-wide RNAi screen with the null allele nud-2(ok949), which compromises dynein function but leaves animals viable and fertile. Using bacterial feeding to deliver dsRNAs in a 96-well liquid format and a semi-automated fluorescence microscopy approach for counting parents and progeny, we screened 19762 bacterial clones and identified 38 genes whose inhibition caused enhanced lethality in nud-2(ok949) relative to the nud-2(+) control. Further study of these genes, many of which participate in cell division, promises to provide insight into the function and regulation of dynein.The authors acknowledge the support of the BioSciences Screening i3S Scientific Platform. Funding for this project was provided by the European Research Council under the European Union's Seventh Framework Programme (ERC grant agreement n o ERC-2013-StG-338410-DYNEINOME to R.G.), by the European Molecular Biology Organization (EMBO Installation Grant 2545 to R.G.), by the Fundacao para a Ciencia e a Tecnologia (IF/01015/2013/CP1157/CT0006 to R.G. and SFRH/BD/103495/2014 to H. R.), and by 'Norte-01-0145-FEDER-000029-Advancing cancer research: from basic knowledge to application', supported by the Norte Portugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement through the European Regional Development Fund (FEDER

NudE regulates dynein at kinetochores but is dispensable for other dynein functions in the C. elegans early embryo

In mitosis, themolecular motor dynein is recruited to kinetochores by the Rod-Zw10-Zwilch complex (RZZ) and Spindly to control spindle assembly checkpoint (SAC) signaling and microtubule attachment. How the ubiquitous dynein co-factors Lis1 and NudE contribute to these functions remains poorly understood. Here, we show that the C. elegans NudE homolog NUD-2 is dispensable for dynein- and LIS-1-dependent mitotic spindle assembly in the zygote. This facilitates functional characterization of kinetochore-localized NUD-2, which is recruited by the CENP-F-like proteins HCP-1 and HCP-2 independently of RZZ- Spindly and dynein-LIS-1. Kinetochore dynein levels are reduced in ¿nud-2 embryos, and, as occurs upon RZZ inhibition, loss of NUD-2 delays the formation of load-bearing kinetochore-microtubule attachments and causes chromatin bridges in anaphase. Survival of ¿nud-2 embryos requires a functional SAC, and kinetochores without NUD-2 recruit an excess of SAC proteins. Consistent with this, SAC signaling in early ¿nud-2 embryos extends mitotic duration and prevents high rates of chromosome mis-segregation. Our results reveal that both NUD-2 and RZZ-Spindly are essential for dynein function at kinetochores, and that the gain in SAC strength during early embryonic development is relevant under conditions that mildly perturb mitosis.This project was funded by the European Research Council under the European Union’s Seventh Framework Programme (ERC grant agreement no. ERC-2013-StG-338410-DYNEINOME to R.G.), and the European Union’s Horizon 2020 Research and Innovation Programme (ERC grant agreement no. ERC-2014-StG-640553-ACTOMYO to A.X.C.). Additional funding was fromthe European Molecular Biology Organization (Installation Grant; R.G.), from the Fundação para a Ciência e a Tecnologia(IF/01015/2013/CP1157/CT0006; R.G.), and from the project ‘Norte-01-0145-FEDER-000029, Advancing cancer research: from basic knowledge to application’, supported by the Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement through the European Regional Development Fund (FEDER). Deposited in PMC for immediate release

Switching off or switching source : energy consumption and household

"Access to energy is fundamental to improving quality of life and is a key imper- ative for economic development" (Energy Poverty Action). This is particularly true in Central Asia where winters are harsh and long. Changes in energy prices affect the purchasing power of households, hitting the poor in particular. The impact very much depends on a household's energy basket and the available strategies for switching to alternative energy sources. Using data from the Kyrgyz Integrated Household Survey (KIHS) 2011, this paper analyzes the prole of household energy consumption and the impact of electricity tariff increases on the probability that households would switch to alternative energy sources. Results suggest that households would respond to an electricity price increase by increasing consumption of fuels: households would tend to move away from electricity-only heating source towards the use of stove-only

Quantum Dissipative Dynamics of the Magnetic Resonance Force Microscope in the Single-Spin Detection Limit

We study a model of a magnetic resonance force microscope (MRFM) based on the cyclic adiabatic inversion technique as a high-resolution tool to detect single electron spins. We investigate the quantum dynamics of spin and cantilever in the presence of coupling to an environment. To obtain the reduced dynamics of the combined system of spin and cantilever, we use the Feynman-Vernon influence functional and get results valid at any temperature as well as at arbitrary system-bath coupling strength. We propose that the MRFM can be used as a quantum measurement device, i.e., not only to detect the modulus of the spin but also its direction

Behavioural endophenotypes in mice lacking the auxiliary GABAB receptor subunit KCTD16

Gamma-aminobutyric acid (GABA) is the major inhibitory neurotransmitter in the brain and is implicated in the pathophysiology of a number of neuropsychiatric disorders. The GABAB receptors are G-protein coupled receptors consisting of principle subunits and auxiliary potassium channel tetramerization domain (KCTD) subunits. The KCTD subunits 8, 12, 12b and 16 are cytosolic proteins that determine the kinetics of the GABAB receptor response. Previously, we demonstrated that Kctd12 null mutant mice (Kctd12(-/-)) exhibit increased auditory fear learning and that Kctd12(+/-) mice show altered circadian activity, as well as increased intrinsic excitability in hippocampal pyramidal neurons. KCTD16 has been demonstrated to influence neuronal excitability by regulating GABAB receptor-mediated gating of postsynaptic ion channels. In the present study we investigated for behavioural endophenotypes in Kctd16(-/-) and Kctd16(+/-) mice. Compared with wild-type (WT) littermates, auditory and contextual fear conditioning were normal in both Kctd16(-/-) and Kctd16(+/-) mice. When fear memory was tested on the following day, Kctd16(-/-) mice exhibited less extinction of auditory fear memory relative to WT and Kctd16(+/-) mice, as well as more contextual fear memory relative to WT and, in particular, Kctd16(+/-) mice. Relative to WT, both Kctd16(+/-) and Kctd16(-/-) mice exhibited normal circadian activity. This study adds to the evidence that auxillary KCTD subunits of GABAB receptors contribute to the regulation of behaviours that could constitute endophenotypes for hyper-reactivity to aversive stimuli in neuropsychiatric disorders

Low cost microfluidic device for partial cell separation: micromilling approach

Several studies have already demonstrated that it is possible to perform blood flow studies in microfluidic systems fabricated by using low-cost techniques. However, most of these techniques do not produce microchannels smaller than 100 microns and as a result they have several limitations related to blood cell separation. Recently, manufacturers have been able to produce milling tools smaller than 100 microns, which consequently have promoted the ability of micromilling machines to fabricate microfluidic devices able to perform separation of red blood cells (RBCs) from plasma. In this work, we show the ability of a micromilling machine to manufacture microchannels with dimensions down to 30 microns. Additionally, we show for the first time the ability of the proposed microfluidic device to enhance the cell-free layer close to the walls, leading to perform partial separation of RBCs from plasma.The authors acknowledge the financial support provided by PTDC/SAU-ENB/116929/2010 and EXPL/EMSSIS/ 2215/2013 from FCT (Science and Technology Foundation), COMPETE, QREN and European Union (FEDER). RR and DP acknowledge, respectively, the PhD scholarships SFRH/BD/97658/2013 and SFRH/BD/89077/2012 attributed by FCT

A method for determining gas-hydrate or free-gas saturation of porous media from seismic measurements

The occurrence of gas hydrate or free gas in a porous medium changes the medium’s elastic properties. Explicit formulas for gas-hydrate or free-gas saturation of pore space on the basis of the Frenkel-Gassmann equations describe the elastic moduli and seismic velocities of a porous medium for low frequencies. A key assumption of the model is that either gas hydrate or free gas is present in the pore space in addition to water. Under this assumption, the method uses measured P- and S-wave velocities and bulk density along with estimates of the moduli and densities of the solid and fluid phases present to determine whether gas or hydrate is present. The method then determines the saturation level of either the gas or the hydrate. I apply the method to published velocity and density data from seismic studies at the antarctic Shetland margin and at the Storegga slide, offshore Norway, and to borehole log and core data from Ocean Drilling Program (ODP) Leg 164 at Blake Ridge, offshore South Carolina. A sensitivity analysis reveals that the standard deviations of the gas-hydrate and free-gas saturations reach 30%–70% of the saturations if the standard deviations of the P- and S-wave velocities and of the bulk density are 50m∕s ..

Non-Markoffian effects of a simple nonlinear bath

We analyze a model of a nonlinear bath consisting of a single two-level system coupled to a linear bath (a classical noise force in the limit considered here). This allows us to study the effects of a nonlinear, non-Markoffian bath in a particularly simple situation. We analyze the effects of this bath onto the dynamics of a spin by calculating the decay of the equilibrium correlator of the spin's z-component. The exact results are compared with those obtained using three commonly used approximations: a Markoffian master equation for the spin dynamics, a weak-coupling approximation, and the substitution of a linear bath for the original nonlinear bath.Comment: 7 pages, 6 figure