Cloning, properties and tissue distribution of natriuretic peptide receptor-A of euryhaline eel, Anguilla japonica

During the course of cloning and characterization of natriuretic peptide receptor-A (NPR-A) from the euryhaline fish eel, Anguilla japonica, we identified a splice variant with unique structural properties that affect ligand-inducible intrinsic guanylate cyclase activity. The variant, generated from a splice between a cryptic donor site and the normal acceptor site, lacked nine amino acid residues (VFTKTGYYK) in the kinase-like regulatory domain. This deletion of a very short segment resulted in the complete loss of the ligand inducibility of the cyclase activity. The nine-amino acid segment may therefore be useful as a target for studies aimed at clarifying the mechanism of activation of the guanylate cyclase domain. Characterization of the normal form of eel NPR-A also led to the following interesting findings. Although eel NPR-A had a domain structure very similar to that of mammalian counterparts, it lacked the third cysteine residue in the extracellular domain which is conserved among mammalian NPR-A molecules. The eel receptor bound both amidated and nonamidated eel atrial natriuretic peptide (eANP) with high affinity but, when assayed for ligand-inducible cGMP generation, it responded efficiently only to physiological concentrations of the amidated ligand, suggesting that the biologically active form is the amidated eANP, and the nonamidated form acts as a partial antagonist; similarly, nonhomologous rat ligands behaved like antagonists toward the eel receptor in the concentration range 0.1-10 nm. The receptor message was found to be relatively abundant in the osmoregulatory organs such as the gill, kidney, intestine and urinary bladder.     

Anammox Bacterial S-Adenosyl-l-Methionine Dependent Methyltransferase Crystal Structure and Its Interaction with Acyl Carrier Proteins

Ladderane lipids (found in the membranes of anaerobic ammonium-oxidizing [anammox] bacteria) have unique ladder-like hydrophobic groups, and their highly strained exotic structure has attracted the attention of scientists. Although enzymes encoded in type II fatty acid biosynthesis (FASII) gene clusters in anammox bacteria, such as S-adenosyl-l-methionine (SAM)-dependent enzymes, have been proposed to construct a ladder-like structure using a substrate connected to acyl carrier protein from anammox bacteria (AmxACP), no experimental evidence to support this hypothesis was reported to date. Here, we report the crystal structure of a SAM-dependent methyltransferase from anammox bacteria (AmxMT1) that has a substrate and active site pocket between a class I SAM methyltransferase-like core domain and an additional α-helix inserted into the core domain. Structural comparisons with homologous SAM-dependent C-methyltransferases in polyketide synthase, AmxACP pull-down assays, AmxACP/AmxMT1 complex structure predictions by AlphaFold, and a substrate docking simulation suggested that a small compound connected to AmxACP could be inserted into the pocket of AmxMT1, and then the enzyme transfers a methyl group from SAM to the substrate to produce branched lipids. Although the enzymes responsible for constructing the ladder-like structure remain unknown, our study, for the first time, supports the hypothesis that biosynthetic intermediates connected to AmxACP are processed by SAM-dependent enzymes, which are not typically involved in the FASII system, to produce the ladder-like structure of ladderane lipids in anammox bacteria.     

Noninvasive online measurement of particle size and concentration in liquid–particle mixture by estimating equivalent circuit of electrical double layer

ABSTRACT

Three electrical elements (i.e., resistance, capacitance, and relaxation frequency) of electrical double layer (EDL) formed around particles have been extracted by a measuring–fitting combination for a novel noninvasive online measurement technique of particle size and concentration in a liquid–particle mixture. The measuring–fitting combination means measuring the impedances with electrical-impedance spectroscopy (EIS) method, and fitting the equivalent circuit with Levenberg–Marquardt method. The liquid–particle mixture in the impedance measurement is made of sodium chloride solution and stainless particles; the equivalent circuit is established corresponding to the contents in the liquid–particle mixture. As a result, the influence of the particle size and concentration on the electrical elements in the EDL which are the resistance, capacitance, and relaxation frequency in the EDL are clarified and discussed. This method is useful for determination of the particle size and concentration in liquid–particle mixture.     

Electrochemical properties and Li deposition morphologies of surface modified graphite after grinding

Electrochemical properties and Li deposition morphologies of several kinds of carbon with different surfaces were studied. The surface conditions and Li deposition morphologies were analyzed using Raman spectroscopy and scanning electron microscopy. It appeared that the disordered carbon surface suppressed the Li dendrite deposition. Grinding methods with different clearances were adopted to modify the graphite into a desirable surface. The R-value increased from 0.10 to 0.63 after grinding to 40 μm, though a significant change in d_0 0 2 did not occur. These results suggest that disordered carbon was created on the surface without a significant change in bulk crystallinity. Thus, the reversible capacity, which is about 350 mAh g⁻¹, was the same before and after grinding. However, the Li deposition morphologies significantly changed before and after grinding. The pristine graphite had a dendritic morphology, but the ground graphite had a granular morphology. It is believed that the defects on the disordered carbon act as electrodeposition nuclei and prevent the formation of Li dendrites.     

The High-Resolution X-Ray Microcalorimeter Spectrometer, SXS, on Astro-H

The science and an overview of the Soft X-ray Spectrometer onboard the STRO-H mission are presented. The SXS consists of X-ray focusing mirrors and a microcalorimeter array and is developed by international collaboration lead by JAXA and NASA with European participation. The detector is a 6×6 format microcalorimeter array operated at a cryogenic temperature of 50 mK and covers a 3′×3′ field of view of the X-ray telescope of 5.6 m focal length. We expect an energy resolution better than 7 eV (FWHM, requirement) with a goal of 4 eV. The effective area of the instrument will be 225 cm² at 7 keV; by a factor of about two larger than that of the X-ray microcalorimeter on board Suzaku. One of the main scientific objectives of the SXS is to investigate turbulent and/or macroscopic motions of hot gas in clusters of galaxies.     

Extremely bendable, high-performance integrated circuits using semiconducting carbon nanotube networks for digital, analog, and radio-frequency applications

Solution-processed thin-films of semiconducting carbon nanotubes as the channel material for flexible electronics simultaneously offers high performance, low cost, and ambient stability, which significantly outruns the organic semiconductor materials. In this work, we report the use of semiconductor-enriched carbon nanotubes for high-performance integrated circuits on mechanically flexible substrates for digital, analog and radio frequency applications. The as-obtained thin-film transistors (TFTs) exhibit highly uniform device performance with on-current and transconductance up to 15 μA/μm and 4 μS/μm. By performing capacitance-voltage measurements, the gate capacitance of the nanotube TFT is precisely extracted and the corresponding peak effective device mobility is evaluated to be around 50 cm(2)V(-1)s(-1). Using such devices, digital logic gates including inverters, NAND, and NOR gates with superior bending stability have been demonstrated. Moreover, radio frequency measurements show that cutoff frequency of 170 MHz can be achieved in devices with a relatively long channel length of 4 μm, which is sufficient for certain wireless communication applications. This proof-of-concept demonstration indicates that our platform can serve as a foundation for scalable, low-cost, high-performance flexible electronics.     

Self-Aligned, Extremely High Frequency III-V Metal-Oxide-Semiconductor Field-Effect Transistors on Rigid and Flexible Substrates

This paper reports the radio frequency (RF) performance of InAs nanomembrane transistors on both mechanically rigid and flexible substrates. We have employed a self-aligned device architecture by using a T-shaped gate structure to fabricate high performance InAs metal-oxide-semiconductor field-effect transistors (MOSFETs) with channel lengths down to 75 nm. RF measurements reveal that the InAs devices made on a silicon substrate exhibit a cutoff frequency (f(t)) of ～165 GHz, which is one of the best results achieved in III-V MOSFETs on silicon. Similarly, the devices fabricated on a bendable polyimide substrate provide a f(t) of ～105 GHz, representing the best performance achieved for transistors fabricated directly on mechanically flexible substrates. The results demonstrate the potential of III-V-on-insulator platform for extremely high-frequency (EHF) electronics on both conventional silicon and flexible substrates.