A TRPV family ion channel required for hearing in Drosophila

The many types of insect ear share a common sensory element, the chordotonal organ, in which sound-induced antennal or tympanal vibrations are transmitted to ciliated sensory neurons and transduced to receptor potentials. However, the molecular identity of the transducing ion channels in chordotonal neurons, or in any auditory system, is still unknown. Drosophila that are mutant for NOMPC, a transient receptor potential (TRP) superfamily ion channel, lack receptor potentials and currents in tactile bristles but retain most of the antennal sound-evoked response, suggesting that a different channel is the primary transducer in chordotonal organs. Here we describe the Drosophila Nanchung (Nan) protein, an ion channel subunit similar to vanilloid-receptor-related (TRPV) channels of the TRP superfamily. Nan mediates hypo-osmotically activated calcium influx and cation currents in cultured cells. It is expressed in vivo exclusively in chordotonal neurons and is localized to their sensory cilia. Antennal sound-evoked potentials are completely absent in mutants lacking Nan, showing that it is an essential component of the chordotonal mechanotransducer.     

Identification of Lps2 as a key transducer of MyD88-independent TIR signalling

In humans, ten Toll-like receptor (TLR) paralogues sense molecular components of microbes, initiating the production of cytokine mediators that create the inflammatory response. Using N-ethyl-N-nitrosourea, we induced a germline mutation called Lps2, which abolishes cytokine responses to double-stranded RNA and severely impairs responses to the endotoxin lipopolysaccharide (LPS), indicating that TLR3 and TLR4 might share a specific, proximal transducer. Here we identify the Lps2 mutation: a distal frameshift error in a Toll/interleukin-1 receptor/resistance (TIR) adaptor protein known as Trif or Ticam-1. Trif(Lps2) homozygotes are markedly resistant to the toxic effects of LPS, and are hypersusceptible to mouse cytomegalovirus, failing to produce type I interferons when infected. Compound homozygosity for mutations at Trif and MyD88 (a cytoplasmic TIR-domain-containing adaptor protein) loci ablates all responses to LPS, indicating that only two signalling pathways emanate from the LPS receptor. However, a Trif-independent cell population is detectable when Trif(Lps2) mutant macrophages are stimulated with LPS. This reveals that an alternative MyD88-dependent 'adaptor X' pathway is present in some, but not all, macrophages, and implies afferent immune specialization.     

Unified deep learning model for El Nino/Southern Oscillation forecasts by incorporating seasonality in climate data

Although deep learning has achieved a milestone in forecasting the El Nino-Southern Oscillation(ENSO),the current models are insufficient to simulate diverse ch...     

Direct measurement of antiferromagnetic domain fluctuations

Measurements of magnetic noise emanating from ferromagnets owing to domain motion were first carried out nearly 100 years ago, and have underpinned much science and technology. Antiferromagnets, which carry no net external magnetic dipole moment, yet have a periodic arrangement of the electron spins extending over macroscopic distances, should also display magnetic noise. However, this must be sampled at spatial wavelengths of the order of several interatomic spacings, rather than the macroscopic scales characteristic of ferromagnets. Here we present a direct measurement of the fluctuations in the nanometre-scale superstructure of spin- and charge-density waves associated with antiferromagnetism in elemental chromium. The technique used is X-ray photon correlation spectroscopy, where coherent X-ray diffraction produces a speckle pattern that serves as a 'fingerprint' of a particular magnetic domain configuration. The temporal evolution of the patterns corresponds to domain walls advancing and retreating over micrometre distances. This work demonstrates a useful measurement tool for antiferromagnetic domain wall engineering, but also reveals a fundamental finding about spin dynamics in the simplest antiferromagnet: although the domain wall motion is thermally activated at temperatures above 100 K, it is not so at lower temperatures, and indeed has a rate that saturates at a finite value-consistent with quantum fluctuations-on cooling below 40 K.     

Network anatomy and in vivo physiology of visual cortical neurons

In the cerebral cortex, local circuits consist of tens of thousands of neurons, each of which makes thousands of synaptic connections. Perhaps the biggest impediment to understanding these networks is that we have no wiring diagrams of their interconnections. Even if we had a partial or complete wiring diagram, however, understanding the network would also require information about each neuron's function. Here we show that the relationship between structure and function can be studied in the cortex with a combination of in vivo physiology and network anatomy. We used two-photon calcium imaging to characterize a functional property--the preferred stimulus orientation--of a group of neurons in the mouse primary visual cortex. Large-scale electron microscopy of serial thin sections was then used to trace a portion of these neurons' local network. Consistent with a prediction from recent physiological experiments, inhibitory interneurons received convergent anatomical input from nearby excitatory neurons with a broad range of preferred orientations, although weak biases could not be rejected.