Self-assembled multilayer graphene oxide membrane and carbon nanotubes synthesized using a rare form of natural graphite

The fabrication of flexible multilayer graphene oxide (GO) membrane and carbon nanotubes (CNTs) using a rare form of high-purity natural graphite, vein graphite, is reported for the first time. Graphite oxide is synthesized using vein graphite following Hummer's method. By facilitating functionalized graphene sheets in graphite oxide to self-assemble, a multilayer GO membrane is fabricated. Electric arc discharge is used to synthesis CNTs from vein graphite. Both multilayer GO membrane and CNTs are investigated using microscopy and spectroscopy experiments, i.e., scanning electron microscopy (SEM), atomic force microscopy (AFM), high-resolution transmission electron microscopy (HRTEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), core level photoelectron spectroscopy, and C K-edge X-ray absorption spectroscopy (NEXAFS), to characterize their structural and topographical properties. Characterization of vein graphite using different techniques reveals that it has a large number of crystallites, hence the large number of graphene sheets per crystallite, preferentially oriented along the (002) plane. NEXAFS and core level spectra confirm that vein graphite is highly crystalline and pure. Fourier transform infrared (FT-IR) and C 1s core level spectra show that oxygen functionalities (-C-OH, -CO,-C-O-C-) are introduced into the basal plane of graphite following chemical oxidation. Carbon nanotubes are produced from vein graphite through arc discharge without the use of any catalyst. HRTEM confirm that multiwalled carbon nanotube (MWNTs) are produced with the presence of some structure in the central pipe. A small percentage of single-walled nanotubes (SWNTs) are also produced simultaneously with MWNTs. Spectroscopic and microscopic data are further discussed here with a view to using vein graphite as the source material for the synthesis of carbon nanomaterials. © 2013 American Chemical Society.

A new approach to the analytical and numerical form-finding of tensegrity structures

We develop a new formulation for the form-finding of tensegrity structures in which the primary variables are the Cartesian components of element lengths. Both an analytical and a numerical implementation of the formulation are described; each require a description of the connectivity of the tensegrity, with the iterative numerical method also requiring a random starting vector of member force densities. The analytical and numerical form-finding of tensegrity structures is demonstrated through six examples, and the results obtained are compared and contrasted with those available in the literature to verify the accuracy and viability of the suggested methods. © 2013 Elsevier Ltd. All rights reserved.

Why do Chinese alligators (Alligator sinensis) form bellowing choruses: A playback approach

Crocodilians are quite vocal relative to other reptile groups, and the alligators are among the most vocal of the crocodilians. The Chinese alligator, Alligator sinensis, is usually solitary but engages in bellowing choruses in certain waters during the mating season. This paper reports the organization of Chinese alligator's bellowing choruses based upon field observations and playback experiments. Alligators of both genders engaged in the choruses, remaining immobile throughout and inclining toward bellowing synchronously (i.e., starting and finishing at about the same time). The choruses lasted about 10 min with abrupt onset and offset. Moreover, playback experiments revealed that both male and female alligators responded equally to bellowing stimuli from the same and opposite sexes and that none of the tested alligators approached the loudspeaker in spite of playback of male or female stimuli. These suggest that Chinese alligators. may not bellow to compete for or attract mates during the choruses. Instead, when their ecological behaviors, namely, dispersed inhabitation, multi-copulation, restricted mating season, etc., are considered, we hypothesize that they may synchronize bellows to enhance group detectability for assembling individuals into certain waters for subsequent copulations. (C) 2009 Acoustical Society of America. [DOI: 10.1121/1.3203667]

Subcellular localization and inductive expression of the dsRNA-dependent protein kinase PKR from Japanese flounder, Paralichthys olivaceus

The double-stranded RNA (dsRNA)-dependent protein kinase (PKR) belongs to the eIF2 alpha kinase family and plays a critical role in interferon (IFN)-mediated antiviral response. Recently, in Japanese flounder (Paralichthys olivaceus), a PKR gene has been identified. In this study, we showed that PoPKR localized to the cytoplasm, and the dsRNA-binding motifs (dsRBMs) played a determinative role in protein localization. In cultured FEC cells, PoPKR was detected at a low level of constitutive expression but was highly induced after treatment with UV-inactivated grass carp hemorrhagic virus, active SMRV and Poly I:C although with different expression kinetics. In flounder, PoPKR was ubiquitously distributed in all tested tissues, and SMRV infection resulted in significant upregulation at mRNA and protein levels. In order to reveal the role of PoPKR in host antiviral response, its expression upon exposure to various inducers was characterized and further compared with that of PoHRI, which is another eIF2 alpha kinase of flounder. Interestingly, expression comparison revealed that all inducers stimulated upregulation of PoHRI in cultured flounder embryonic cells and fish, with a similar kinetics to PoPKR but to a less extent. These results suggest that, during antiviral immune response, both flounder eIF2 alpha kinases might play similar roles and that PoPKR is the predominant kinase. (C) 2009 National Natural Science Foundation of China and Chinese Academy of Sciences. Published by Elsevier Limited and Science in China Press. All rights reserved.

Rana grylio virus thymidine kinase gene: an early gene of iridovirus encoding for a cytoplasmic protein

The presence of thymidine kinase (TK) is a feature of many large DNA viruses. Here, a TK gene homologue was cloned and characterized from Rana grylio virus (RGV), a member of family Iridoviridae. RGV TK encodes a protein of 195 aa with a predicted molecular mass of 22.1 kDa. Homologues of the protein were present in all the currently sequenced iridoviruses, and phylogenetic analysis showed that it was much close to cellular TK type 2 (TK2), deoxycytidine kinase (dCK) and deoxyguanosine kinase (dGK). Subsequently, Western blotting revealed TK expression increased with time from 6 h post-infection in RGV-infected cells. Using drug inhibition analysis by protein synthesis inhibitor (cycloheximide) and DNA replication inhibitor (cytosine arabinofuranoside), RGV TK was classified as the early expression gene during in vitro infection. Subcellular localization by TK-GFP fusion protein expression and immunofluorescence staining showed RGV TK was an exclusively cytoplasmic protein in fish cells. Collectively, current data indicate that RGV TK was an early gene of iridovirus which encoded a cytoplasmic protein in fish cells.

Functional domains and the antiviral effect of the double-stranded RNA-dependent protein kinase PKR from Paralichthys olivaceus

The double-stranded RNA (dsRNA)-dependent protein kinase PKR is thought to mediate a conserved antiviral pathway by inhibiting viral protein synthesis via the phosphorylation of the alpha subunit of eukaryotic initiation factor 2 (eIF2 alpha). However, little is known about the data related to the lower vertebrates, including fish. Recently, the identification of PKR-like, or PKZ, has addressed the question of whether there is an orthologous PKR in fish. Here, we identify the first fish PKR gene from the Japanese flounder Paralichthys olivaceus (PoPKR). PoPKR encodes a protein that shows a conserved structure that is characteristic of mammalian PKRs, having both the N-terminal region for dsRNA binding and the C-terminal region for the inhibition of protein translation. The catalytic activity of PoPKR is further evidence that it is required for protein translation inhibition in vitro. PoPKR is constitutively transcribed at low levels and is highly induced after virus infection. Strikingly, PoPKR overexpression increases eIF2 alpha phosphorylation and inhibits the replication of Scophthalmus maximus rhabdovirus (SMRV) in flounder embryonic cells, whereas phosphorylation and antiviral effects are impaired in transfected cells expressing the catalytically inactive PKR-K421R variant, indicating that PoPKR inhibits virus replication by phosphorylating substrate eIF2 alpha. The interaction between PoPKR and eIF2 alpha is demonstrated by coimmunoprecipitation assays, and the transfection of PoPKR-specific short interfering RNA further reveals that the enhanced eIF2 alpha phosphorylation is catalyzed by PoPKR during SMRV infection. The current data provide significant evidence for the existence of a PKR-mediated antiviral pathway in fish and reveal considerable conservation in the functional domains and the antiviral effect of PKR proteins between fish and mammals.

Predicted glycosyl transferase genes located outside the HEP island are required for formation of heterocyst envelope polysaccharide in Anabaena sp strain PCC 7120

During maturation, heterocysts form an envelope layer of polysaccharide, called heterocyst envelope polysaccharide (HEP), whose synthesis depends on a cluster of genes, the HEP island, and on an additional, distant gene, hepB, or a gene immediately downstream from hepB. We show that HEP formation depends upon the predicted glycosyl transferase genes all4160 at a third locus and alr3699, which is adjacent to hepB and is cotranscribed with it. Mutations in the histidine kinase genes hepN and hepK appear to silence the promoter of hepB and incompletely down-regulate all4160.

Unified form language: A domain-specific language for weak formulations of partial differential equations

We present the Unified Form Language (UFL), which is a domain-specific language for representing weak formulations of partial differential equations with a view to numerical approximation. Features of UFL include support for variational forms and functionals, automatic differentiation of forms and expressions, arbitrary function space hierarchies formultifield problems, general differential operators and flexible tensor algebra. With these features, UFL has been used to effortlessly express finite element methods for complex systems of partial differential equations in near-mathematical notation, resulting in compact, intuitive and readable programs. We present in this work the language and its construction. An implementation of UFL is freely available as an open-source software library. The library generates abstract syntax tree representations of variational problems, which are used by other software libraries to generate concrete low-level implementations. Some application examples are presented and libraries that support UFL are highlighted. © 2014 ACM.

Identification of genome organization in the unusual allotetraploid form of Carassius auratus gibelio

The unusual allotetraploid form with unequal contribution of chromosome sets was discovered from the gynogenetic offspring of Carassius auratus gibelio stimulated by red common carp sperm. In this study, genomic in situ hybridization (GISH) and fluorescent in situ hybridization (FISH) with 45S rDNA probe are used. The GISH results lead to the identification of species-specific chromosomes, which permits to demonstrate the origin and genome organization in the allotetraploid form. Moreover, chromosome localization of 45S rDNA and co-localizations of 45S rDNA and Cyprinus carpio genomic DNA further confirm that one extra 45S rDNA positive chromosome in the allotetraploid form originates from the paternal haploid genome of C carpio, and other 5 45S rDNA-containing chromosomes are from the maternal genome of Carassius auratus gibelio. And, the correlation between 45 rDNA and the nucleolar organizer regions (NORs) is confirmed by silver nitrate staining. The data provide direct experiment evidence that the allotetraploid actually contains three chromosome sets of Carassius auratus gibelio and one chromosome set of C carpio, and will be a useful genetic material for both basic research and breeding practice. (c) 2006 Elsevier B.V. All rights reserved.

Changes in the benthic macroinvertebrates in Xiangxi Bay following dam closure to form the Three Gorges Reservoir

Benthic macroinvertebrates were assessed monthly in Xiangxi Bay of the Three Gorges Reservoir for two years after the initial closure of the dam. Mean total density of macroinvertebrates varied from 275 ind./m(2) during the first year to 5,094 ind./m(2) during the second year, and the community of 50 taxa was overwhelmingly dominated by oligochaetes and chironomids (44 and 48% of the total taxa, respectively). As sediment accumulated in the substrate of the bay, the species composition changed dramatically, with oligochaetes comprising 91.3-99.3% of the total abundance during the second year. The dominant oligochaetes were Limnodrilus hoffmeisteri and Nais inflata. The chironomids Procladius sp., and Polypedilum scalaenum group sp. were similarly abundant in both years.

Molecular cloning and stress-induced expression of paralichthys olivaceus heme-regulated initiation factor 2 alpha kinase

The heme-regulated initiation factor 2 alpha kinase (HRI) is acknowledged to play an important role in translational shutoff in reticulocytes in response to various cellular stresses. In this study, we report its homologous cDNA cloning and characterization from cultured flounder embryonic cells (FEC) after treatment with UV-inactivated grass carp haemorrhagic virus (GCHV). The full-length cDNA of Paralichthys olivaceus HRI homologue (PoHRI) has 2391 bp and encodes a protein of 651 amino acids. The putative PoHRI protein exhibits high identity with all members of eIF2 alpha kinase family. It contains 12 catalytic subdomains located within the C-terminus of all Ser/Thr protein kinases, a unique kinase insertion of 136 amino acids between subdomains IV and V, and a relatively conserved N-terminal domain (NTD). Upon heat shock, virus infection or Poly PC treatment, PoHRI mRNA and protein are significantly upregulated in FEC cells but show different expression patterns in response to different stresses. In healthy flounders, PoHRI displays a wide tissue distribution at both the mRNA and protein levels. These results indicate that PoHRI is a ubiquitous eIF2a kinase and might play an important role in translational control over nonheme producing FEC cells under different stresses. (c) 2006 Elsevier Ltd. All rights reserved.

alr0117, a two-component histidine kinase gene, is involved in heterocyst development in Anabaena sp PCC 7120

Anabaena sp. PCC; 7120 was mutagenized by transposon Tn5-1087b, generating a mutant whose heterocysts lack the envelope polysaccharide layer. The transposon was located between nucleotides 342 and 343 of alr0117, a 918 bp gene encoding a histidine kinase for a two-component regulatory system. Complementation of the mutant with a DNA fragment containing alr0117 and targeted inactivation of the gene confirmed that alr0117 is involved in heterocyst development. RT-PCR showed that alr0117 was constitutively expressed in the presence or absence of a combined-nitrogen source. hepA and patB, the two genes turned on during wild-type heterocyst development, were no longer activated in an alr0117-null mutant. The two-component signal transduction system involving alr0117 may control the formation of the envelope polysaccharide layer and certain late events essential to the function of heterocysts.

pkn22 (alr2502) encoding a putative Ser/Thr kinase in the cyanobacterium Anabaena sp PCC 7120 is induced by both iron starvation and oxidative stress and regulates the expression of isiA

In cyanobacteria, the isiA gene is required for cell adaptation to oxidative damage caused by the absence of iron. We show here that a putative Ser/Thr kinase gene, pkn22 (alr2052), is activated by iron deficiency and oxidative damage in Anabaena sp. PCC 7120. A pkn22 insertion mutant is unable to grow when iron is limiting. pkn22 regulates the expression of isiA (encoding CP43') but not of isiB (encoding flavodoxin) and psbC (CP43). Fluorescence measurement at 77 K reveals the absence of the typical signature of CP43' associated with photosystem I in the mutant under iron-limiting conditions. We propose that Pkn22 is required for the function of isiA/CP43' and constitutes a regulatory element necessary for stress response. (C) 2003 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Transgenes in F-4 pMThGH-transgenic common carp (Cyprinus carpio L.) are highly polymorphic

To gain information on the integration pattern of pMThGH-transgene, 50 transgenes were recovered from F-4 generation of pMThGH transgenic common carp (Cyprinus carpio L,) and 33 recovered genes were analyzed. The restriction maps of these recovered genes were constructed by digestion with five kinds of enzymes. These transgenes can be classified into 4 types according to their restriction maps. Only one type of transgenes maintains its original molecular form, whereas the other three types are very different from the original one and vary each other on both molecular weight and restriction maps. This implies that the sequences of most transgenes have been deleted and/or rearranged during integration and inheritance. The results of PCR amplification and Southern blot hybridization indicate that MThGH in Type I transgene keeps intact but most of its sequence has been deleted in other three types. All these results suggest that transgenes in F-4 generation of transgenic carp are highly polymorphic. Two DNA fragments concerning integration site of transgenes were cloned from recovered transgenes, and found to be homologous to the 5'UTR of beta -actin gene of common carp and mouse mRNA for receptor tyrosine kinase (RTK), respectively.

Oscillatory change of SR-protein kinase activities during oocyte maturation meiosis in fish

The SR-protein kinase activity was analyzed and the cytological changes were observed during oocyte maturation in bisexual transparent color crucian carp ( Carassius auratus color variety). The results revealed that the SR-protein kinase activity was sensitive to the artificially induced spawning hormones, and the change of oscillatory activity was similar to that of the maturation-promoting factor (MPF) kinase that regulates meiotic cell cycle in fish.