Optical probes for the detection of protons, and alkali and alkaline earth metal cations

Chem. Soc. Rev., 2015, Advance Article
DOI: 10.1039/C4CS00365A, Review Article
Graham R. C. Hamilton, Suban K. Sahoo, Sukanta Kamila, Narinder Singh, Navneet Kaur, Barry W. Hyland, John F. Callan
Luminescent sensors and switches continue to play a key role in shaping our understanding of key biochemical processes, assist in the diagnosis of disease and contribute to the design of new drugs and therapies.
To cite this article before page numbers are assigned, use the DOI form of citation above.
The content of this RSS Feed (c) The Royal Society of Chemistry

Neuroscience: Hot on the trail of temperature processing.

Neuroscience: Hot on the trail of temperature processing.

Nature. 2015 Mar 4;

Authors: Florence T, Reiser MB

PMID: 25739498 [PubMed - as supplied by publisher]

Multi-omics of permafrost, active layer and thermokarst bog soil microbiomes.

Multi-omics of permafrost, active layer and thermokarst bog soil microbiomes.

Nature. 2015 Mar 4;

Authors: Hultman J, Waldrop MP, Mackelprang R, David MM, McFarland J, Blazewicz SJ, Harden J, Turetsky MR, McGuire AD, Shah MB, VerBerkmoes NC, Lee LH, Mavrommatis K, Jansson JK

Abstract

Over 20% of Earth’s terrestrial surface is underlain by permafrost with vast stores of carbon that, once thawed, may represent the largest future transfer of carbon from the biosphere to the atmosphere. This process is largely dependent on microbial responses, but we know little about microbial activity in intact, let alone in thawing, permafrost. Molecular approaches have recently revealed the identities and functional gene composition of microorganisms in some permafrost soils and a rapid shift in functional gene composition during short-term thaw experiments. However, the fate of permafrost carbon depends on climatic, hydrological and microbial responses to thaw at decadal scales. Here we use the combination of several molecular ‘omics’ approaches to determine the phylogenetic composition of the microbial communities, including several draft genomes of novel species, their functional potential and activity in soils representing different states of thaw: intact permafrost, seasonally thawed active layer and thermokarst bog. The multi-omics strategy reveals a good correlation of process rates to omics data for dominant processes, such as methanogenesis in the bog, as well as novel survival strategies for potentially active microbes in permafrost.

PMID: 25739499 [PubMed - as supplied by publisher]

Corrigendum: Endocrinization of FGF1 produces a neomorphic and potent insulin sensitizer.

Corrigendum: Endocrinization of FGF1 produces a neomorphic and potent insulin sensitizer.

Nature. 2015 Mar 4;

Authors: Suh JM, Jonker JW, Ahmadian M, Goetz R, Lackey D, Osborn O, Huang Z, Liu W, Yoshihara E, van Dijk TH, Havinga R, Fan W, Yin YQ, Yu RT, Liddle C, Atkins AR, Olefsky JM, Mohammadi M, Downes M, Evans RM

PMID: 25739500 [PubMed - as supplied by publisher]

Regulation of star formation in giant galaxies by precipitation, feedback and conduction.

Regulation of star formation in giant galaxies by precipitation, feedback and conduction.

Nature. 2015 Mar 4;

Authors: Voit GM, Donahue M, Bryan GL, McDonald M

Abstract

The Universe’s largest galaxies reside at the centres of galaxy clusters and are embedded in hot gas that, if left undisturbed, would cool quickly and create many more new stars than are actually observed. Cooling can be regulated by feedback from accretion of cooling gas onto the central black hole, but requires an accretion rate finely tuned to the thermodynamic state of the hot gas. Theoretical models in which cold clouds precipitate out of the hot gas via thermal instability and accrete onto the black hole exhibit the necessary tuning. Recent observational evidence shows that the abundance of cold gas in the centres of clusters increases rapidly near the predicted threshold for instability. Here we report observations showing that this precipitation threshold extends over a large range in cluster radius, cluster mass and cosmic time. We incorporate the precipitation threshold into a framework of theoretical models for the thermodynamic state of hot gas in galaxy clusters. According to that framework, precipitation regulates star formation in some giant galaxies, while thermal conduction prevents star formation in others if it can compensate for radiative cooling and shut off precipitation.

PMID: 25739501 [PubMed - as supplied by publisher]

Thermosensory processing in the Drosophila brain.

Thermosensory processing in the Drosophila brain.

Nature. 2015 Mar 4;

Authors: Liu WW, Mazor O, Wilson RI

Abstract

In Drosophila, just as in vertebrates, changes in external temperature are encoded by bidirectional opponent thermoreceptor cells: some cells are excited by warming and inhibited by cooling, whereas others are excited by cooling and inhibited by warming. The central circuits that process these signals are not understood. In Drosophila, a specific brain region receives input from thermoreceptor cells. Here we show that distinct genetically identified projection neurons (PNs) in this brain region are excited by cooling, warming, or both. The PNs excited by cooling receive mainly feed-forward excitation from cool thermoreceptors. In contrast, the PNs excited by warming (‘warm-PNs’) receive both excitation from warm thermoreceptors and crossover inhibition from cool thermoreceptors through inhibitory interneurons. Notably, this crossover inhibition elicits warming-evoked excitation, because warming suppresses tonic activity in cool thermoreceptors. This in turn disinhibits warm-PNs and sums with feed-forward excitation evoked by warming. Crossover inhibition could cancel non-thermal activity (noise) that is positively correlated among warm and cool thermoreceptor cells, while reinforcing thermal activity which is anti-correlated. Our results show how central circuits can combine signals from bidirectional opponent neurons to construct sensitive and robust neural codes.

PMID: 25739502 [PubMed - as supplied by publisher]

Regulated eukaryotic DNA replication origin firing with purified proteins.

Regulated eukaryotic DNA replication origin firing with purified proteins.

Nature. 2015 Mar 4;

Authors: Yeeles JT, Deegan TD, Janska A, Early A, Diffley JF

Abstract

Eukaryotic cells initiate DNA replication from multiple origins, which must be tightly regulated to promote precise genome duplication in every cell cycle. To accomplish this, initiation is partitioned into two temporally discrete steps: a double hexameric minichromosome maintenance (MCM) complex is first loaded at replication origins during G1 phase, and then converted to the active CMG (Cdc45-MCM-GINS) helicase during S phase. Here we describe the reconstitution of budding yeast DNA replication initiation with 16 purified replication factors, made from 42 polypeptides. Origin-dependent initiation recapitulates regulation seen in vivo. Cyclin-dependent kinase (CDK) inhibits MCM loading by phosphorylating the origin recognition complex (ORC) and promotes CMG formation by phosphorylating Sld2 and Sld3. Dbf4-dependent kinase (DDK) promotes replication by phosphorylating MCM, and can act either before or after CDK. These experiments define the minimum complement of proteins, protein kinase substrates and co-factors required for regulated eukaryotic DNA replication.

PMID: 25739503 [PubMed - as supplied by publisher]

Corrigendum: Human gut Bacteroidetes can utilize yeast mannan through a selfish mechanism.

Corrigendum: Human gut Bacteroidetes can utilize yeast mannan through a selfish mechanism.

Nature. 2015 Mar 4;

Authors: Cuskin F, Lowe EC, Temple MJ, Zhu Y, Cameron EA, Pudlo NA, Porter NT, Urs K, Thompson AJ, Cartmell A, Rogowski A, Hamilton BS, Chen R, Tolbert TJ, Piens K, Bracke D, Vervecken W, Hakki Z, Speciale G, Munōz-Munōz JL, Day A, Peña MJ, McLean R, Suits MD, Boraston AB, Atherly T, Ziemer CJ, Williams SJ, Davies GJ, Abbott DW, Martens EC, Gilbert HJ

PMID: 25739504 [PubMed - as supplied by publisher]

A direct GABAergic output from the basal ganglia to frontal cortex.

A direct GABAergic output from the basal ganglia to frontal cortex.

Nature. 2015 Mar 4;

Authors: Saunders A, Oldenburg IA, Berezovskii VK, Johnson CA, Kingery ND, Elliott HL, Xie T, Gerfen CR, Sabatini BL

Abstract

The basal ganglia are phylogenetically conserved subcortical nuclei necessary for coordinated motor action and reward learning. Current models postulate that the basal ganglia modulate cerebral cortex indirectly via an inhibitory output to thalamus, bidirectionally controlled by direct- and indirect-pathway striatal projection neurons (dSPNs and iSPNs, respectively). The basal ganglia thalamic output sculpts cortical activity by interacting with signals from sensory and motor systems. Here we describe a direct projection from the globus pallidus externus (GP), a central nucleus of the basal ganglia, to frontal regions of the cerebral cortex (FC). Two cell types make up the GP-FC projection, distinguished by their electrophysiological properties, cortical projections and expression of choline acetyltransferase (ChAT), a synthetic enzyme for the neurotransmitter acetylcholine (ACh). Despite these differences, ChAT(+) cells, which have been historically identified as an extension of the nucleus basalis, as well as ChAT(-) cells, release the inhibitory neurotransmitter GABA (γ-aminobutyric acid) and are inhibited by iSPNs and dSPNs of dorsal striatum. Thus, GP-FC cells comprise a direct GABAergic/cholinergic projection under the control of striatum that activates frontal cortex in vivo. Furthermore, iSPN inhibition of GP-FC cells is sensitive to dopamine 2 receptor signalling, revealing a pathway by which drugs that target dopamine receptors for the treatment of neuropsychiatric disorders can act in the basal ganglia to modulate frontal cortices.

PMID: 25739505 [PubMed - as supplied by publisher]

Temperature representation in the Drosophila brain.

Temperature representation in the Drosophila brain.

Nature. 2015 Mar 4;

Authors: Frank DD, Jouandet GC, Kearney PJ, Macpherson LJ, Gallio M

Abstract

In Drosophila, rapid temperature changes are detected at the periphery by dedicated receptors forming a simple sensory map for hot and cold in the brain. However, flies show a host of complex innate and learned responses to temperature, indicating that they are able to extract a range of information from this simple input. Here we define the anatomical and physiological repertoire for temperature representation in the Drosophila brain. First, we use a photolabelling strategy to trace the connections that relay peripheral thermosensory information to higher brain centres, and show that they largely converge onto three target regions: the mushroom body, the lateral horn (both of which are well known centres for sensory processing) and the posterior lateral protocerebrum, a region we now define as a major site of thermosensory representation. Next, using in vivo calcium imaging, we describe the thermosensory projection neurons selectively activated by hot or cold stimuli. Fast-adapting neurons display transient ON and OFF responses and track rapid temperature shifts remarkably well, while slow-adapting cell responses better reflect the magnitude of simple thermal changes. Unexpectedly, we also find a population of broadly tuned cells that respond to both heating and cooling, and show that they are required for normal behavioural avoidance of both hot and cold in a simple two-choice temperature preference assay. Taken together, our results uncover a coordinated ensemble of neural responses to temperature in the Drosophila brain, demonstrate that a broadly tuned thermal line contributes to rapid avoidance behaviour, and illustrate how stimulus quality, temporal structure, and intensity can be extracted from a simple glomerular map at a single synaptic station.

PMID: 25739506 [PubMed - as supplied by publisher]