2,2′-[1,1′-(Propane-1,3-diyldioxy­dinitrilo)diethyl­idyne]di-1-naphthol

The mol­ecule of the title compound, C27H26N2O4, lies across a crystallographic inversion centre and adopts an l-shaped configuration. Within the mol­ecule, the two naphthalene units are approximately perpendicular, making a dihedral angle of 80.24 (5)°. The two intramolecular O—H⋯N hydrogen bonds, generate S(6) ring motifs. In the crystal structure, every mol­ecule links five other mol­ecules into an infinite cross-linked layered supra­molecular structure via inter­molecular C—H⋯O hydrogen bonds, C—H⋯π inter­actions and π–π stacking inter­actions [centroid–centroid distance = 3.956 (4) Å]

Identification and Nearly Full-Length Genome Characterization of Novel Porcine Bocaviruses

The genus bocavirus includes bovine parvovirus (BPV), minute virus of canines (MVC), and a group of human bocaviruses (HBoV1-4). Using sequence-independent single primer amplification (SISPA), a novel bocavirus group was discovered with high prevalence (12.59%) in piglet stool samples. Two nearly full-length genome sequences were obtained, which were approximately 5,100 nucleotides in length. Multiple alignments revealed that they share 28.7–56.8% DNA sequence identity with other members of Parvovirinae. Phylogenetic analyses indicated their closest neighbors were members of the genus bocavirus. The new viruses had a putative non-structural NP1 protein, which was unique to bocaviruses. They were provisionally named porcine bocavirus 1 and 2 (PBoV1, PBoV2). PBoV1 and PBoV2 shared 94.2% nucleotide identity in NS1 gene sequence, suggesting that they represented two different bocavirus species. Two additional samples (6V, 7V) were amplified for 2,407 bp and 2,434 bp products, respectively, including a partial NP1 gene and the complete VP1 gene; Phylogenetic analysis indicated that 6Vand 7V grouped with PBoV1 and PBoV2 in the genus of bocavirus, but were in the separate clusters. Like other parvoviruses, PBoV1, PBoV2, 6Vand 7V also contained a putative secretory phospholipase A2 (sPLA2) motif in the VP1 unique region, with a conserved HDXXY motif in the catalytic center. The conserved motif YXGXF of the Ca2+-binding loop of sPLA2 identified in human bocavirus was also found in porcine bocavirus, which differs from the YXGXG motif carried by most other parvoviruses. The observation of PBoV and potentially other new bocavirus genus members may aid in molecular and functional characterization of the genus bocavirus

Ultrafast Switching from the Charge Density Wave Phase to a Metastable Metallic State in 1T-TiSe2_2

The ultrafast electronic structures of the charge density wave material 1T-TiSe$_2$ were investigated by high-resolution time- and angle-resolved photoemission spectroscopy. We found that the quasiparticle populations drove ultrafast electronic phase transitions in 1T-TiSe$_2$ within 100 fs after photoexcitation, and a metastable metallic state, which was significantly different from the equilibrium normal phase, was evidenced far below the charge density wave transition temperature. Detailed time- and pump-fluence-dependent experiments revealed that the photoinduced metastable metallic state was a result of the halted motion of the atoms through the coherent electron-phonon coupling process, and the lifetime of this state was prolonged to picoseconds with the highest pump fluence used in this study. Ultrafast electronic dynamics were well captured by the time-dependent Ginzburg-Landau model. Our work demonstrates a mechanism for realizing novel electronic states by photoinducing coherent motion of atoms in the lattice.Comment: 13 Pages, 10 figure

Genome-wide identification and expression analysis of serine proteases and homologs in the silkworm Bombyx mori

<p>Abstract</p> <p>Background</p> <p>Serine proteases (SPs) and serine proteases homologs (SPHs) are a large group of proteolytic enzymes, with important roles in a variety of physiological processes, such as cell signalling, defense and development. Genome-wide identification and expression analysis of serine proteases and their homologs in the silkworm might provide valuable information about their biological functions.</p> <p>Results</p> <p>In this study, 51 SP genes and 92 SPH genes were systematically identified in the genome of the silkworm <it>Bombyx mori</it>. Phylogenetic analysis indicated that six gene families have been amplified species-specifically in the silkworm, and the members of them showed chromosomal distribution of tandem repeats. Microarray analysis suggests that many silkworm-specific genes, such as members of SP_fam12, 13, 14 and 15, show expression patterns that are specific to tissues or developmental stages. The roles of SPs and SPHs in resisting pathogens were investigated in silkworms when they were infected by <it>Escherichia coli</it>, <it>Bacillus bombysepticus</it>, <it>Batrytis bassiana </it>and <it>B. mori </it><it>nucleopolyhedrovirus</it>, respectively. Microarray experiment and real-time quantitative RT-PCR showed that 18 SP or SPH genes were significantly up-regulated after pathogen induction, suggesting that SP and SPH genes might participate in pathogenic microorganism resistance in <it>B. mori</it>.</p> <p>Conclusion</p> <p>Silkworm SP and SPH genes were identified. Comparative genomics showed that SP and SPH genes belong to a large family, whose members are generated mainly by tandem repeat evolution. We found that silkworm has species-specific SP and SPH genes. Phylogenetic and microarray analyses provide an overview of the silkworm SP and SPHs, and facilitate future functional studies on these enzymes.</p

Robust normalization and guaranteed cost control for a class of uncertain singular Markovian jump systems via hybrid impulsive control

This paper investigates the problem of robust normalization and guaranteed cost control for a class of uncertain singular Markovian jump systems. The uncertainties exhibit in both system matrices and transition rate matrix of the Markovian chain. A new impulsive and proportional-derivative control strategy is presented, where the derivative gain is to make the closed-loop system of the singular plant to be a normal one, and the impulsive control part is to make the value of the Lyapunov function does not increase at each time instant of the Markovian switching. A linearization approach via congruence transformations is proposed to solve the controller design problem. The cost function is minimized via solving an optimization problem under the designed control scheme. Finally, three examples (two numerical examples and an RC pulse divider circuit example) are provided to illustrate the effectiveness and applicability of the proposed methods

A multi-layer genome mining and phylogenomic analysis to construct efficient and autonomous efflux system for medium chain fatty acids

Medium-chain fatty acids (MCFAs) are important components for food, pharmaceutical and fuel industries. Nevertheless, engineering microorganisms to produce MCFAs often induces toxicity and stresses towards host strains, which could be alleviated via accelerating the export of MCFAs from cells. However, current secretory systems are inefficient and require inducible promoters. Here, a multi-layer genome mining and phylogenomic analysis was developed to identify efficient efflux transporters. Firstly, based on the genomic mining of 397 strains throughout various representative species, the evolutionary history of efflux transporters was recapitulated, and further experimental analysis revealed that acrE from Citrobacter exhibited the best performance. Secondly, according to the further mining of 797 Citrobacter genomes and 1084 Escherichia genomes, a detailed phylogenomic analysis of efflux transporter-centric genomic vicinities was performed. This led to the identification of efficient efflux pump combination acrE and acrF. These efflux pumps were then combined with the quorum-sensing circuit from Enterococcus faecalis to regulate MCFA efflux in an autonomous manner, which achieved a 4.9-fold boost in MCFA production and firstly demonstrated the efficient and autonomous efflux pump specially for MCFAs. The integrative omics technologies described here are enabling the utilization of the increasingly large database and the effective mining of target gene diversities

Molecular dissection of Neuroligin 2 and Slitrk3 reveals an essential framework for GABAergic synapse development

In the brain, many types of interneurons make functionally diverse inhibitory synapses onto principal neurons. Although numerous molecules have been identified to function in inhibitory synapse development, it remains unknown whether there is a unifying mechanism for development of diverse inhibitory synapses. Here we report a general molecular mechanism underlying hippocampal inhibitory synapse development. In developing neurons, the establishment of GABAergic transmission depends on Neuroligin 2 (NL2), a synaptic cell adhesion molecule (CAM). During maturation, inhibitory synapse development requires both NL2 and Slitrk3 (ST3), another CAM. Importantly, NL2 and ST3 interact with nanomolar affinity through their extracellular domains to synergistically promote synapse development. Selective perturbation of the NL2-ST3 interaction impairs inhibitory synapse development with consequent disruptions in hippocampal network activity and increased seizure susceptibility. Our findings reveal how unique postsynaptic CAMs work in concert to control synaptogenesis and establish a general framework for GABAergic synapse development