The complete chloroplast genome of Dianella ensifolia (Asphodelaceae).

Dianella ensifolia (L.) Redouté 1802 is a plant known for its significant medicinal values. In this study, we presented its chloroplast genome. The length of the chloroplast genome was found to be 156,571 bp, with a GC content of 37.86%. It consisted of a large single-copy (LSC) of 85,318 bp and a small single-copy (SSC) of 18,307 bp, a pair of inverted repeats (IRs) of 26,473 bp each that separated the LSC and SSC regions. The chloroplast genome of D. ensifolia consisted of 114 unique genes, including 80 protein-coding genes, four rRNA genes, and 30 tRNA genes. Through phylogenetic analysis, we identified a close relationship between D. ensifolia and D. nigra. This newly sequenced chloroplast genome not only enhances our understanding of the genome of Dianella, but also provides valuable insights for the evolutionary study of the family Asphodelaceae.

Novel Polyaniline-Silver-Sulfur Nanotube Composite as Cathode Material for Lithium-Sulfur Battery.

The preparation and characterization of a polyaniline-silver-sulfur nanotube composite were reported in this paper. The polyaniline-silver nanotube composite was synthesized via an oxidation-reduction method in the sodium dodecyl sulfate (SDS) solution. After being vulcanized, the polyaniline-silver-sulfur (Poly (AN-Ag-S)) nanotube composite was prepared as active cathode material and assembled into lithium-sulfur (Li-S) batteries with electrolyte and negative electrode materials. When the feed ratio of raw materials (aniline and AgNO3) was 2:1, the initial specific capacity of poly (AN-Ag-S) composite cells reached 1114 mAh/g. The specific capacity was kept at 573 mAh/g, and the capacity retention rate stayed above 51% after 100 cycles. The introduction of Ag into the composite cathode material can effectively solve the poor conductivity of sulfur and improve the Li-S battery performance.

Polysaccharides from Cymbopogon citratus with antitumor and immunomodulatory activity.

UNLABELLED: Abstract Context: Most of the present studies on the antitumor efficiency of Cymbopogon citratus (DC.) Stapf (Gramineae) are limited to its low-mass compounds, and little information about the antitumor activity of polysaccharides from this plant is available. OBJECTIVES: This study focused on the potential antitumor and immunomodulatory activities of polysaccharides (CCPS) from C. citratus. MATERIALS AND METHODS: CCPS was isolated using the water extraction-ethanol precipitation method. The sarcoma 180 (S180) cells-inoculated mice were intraperitoneally administrated with CCPS (30-200 mg/kg/d) for seven consecutive days. The effects of CCPS on tumor growth, thymus and spleen weights, splenocyte proliferation, and cytokine secretion in the tumor-bearing mice were measured. The cytotoxicity of CCPS (50-800 µg/mL) towards S180 cells was also studied. RESULTS: CCPS significantly inhibited the growth of the transplanted S180 tumors, with the inhibition rates ranging from 14.8 to 37.8%. Simultaneously, CCPS dose-dependently improved the immunity of the tumor-bearing mice. With the highest dose of 200 mg/kg/d, the thymus and spleen indices were increased by 21.9 and 91.9%, respectively; ConA- and LSP-induced splenocyte proliferations were increased by 32.7 and 35.3%, respectively. The secretions of interleukin 2 (IL-2), interleukin 6 (IL-6), interleukin 2 (IL-12), and tumor necrosis factor-α (TNF-α) were increased by 103.2, 40.2, 23.6, and 26.3%, respectively. Nevertheless, almost no toxicity of CCPS towards S180 cells was observed, with the maximal inhibition rate less than 15% at the CCPS concentration of 800 µg/mL. CONCLUSION: CCPS exhibited antitumor activity in vivo, and this activity might be achieved by immunoenhancement rather than direct cytotoxicity.

In vitro antioxidant and cytotoxic properties of ethanol extract of Alpinia oxyphylla fruits.

CONTEXT: Alpinia oxyphylla Miquel (Zingiberaceae) is a traditional Chinese herbal medicine widely used for the treatment of intestinal disorders, urosis and diuresis. However, information about antioxidant and cytotoxic properties of its fruits remains to be elucidated. OBJECTIVE: The ethanol crude extract (CE) and its fractions [petroleum ether fraction (PF), ethyl acetate fraction (EF), n-butanol fraction (BF) and water fraction (WF) extracted by petroleum ether, ethyl acetate, n-butanol and water, respectively] of A. oxyphylla fruits were investigated for their antioxidant activity and cytotoxicity. MATERIALS AND METHODS: The total phenolic content (TPC) and antioxidant activity of the extracts were determined by Folin-Ciocalteu reagent, 1,1-diphenyl-2-picrylhydrazyl (DPPH(•)), Trolox equivalent antioxidant capacity and reducing power assay. Cytotoxicity of the extracts (0-200 µg/mL) was tested on six human cancer cell lines (breast cancer cell line, cervix carcinoma cell line, lung adenocarcinoma cell line, liver carcinoma cell line, gastric cancer cell line and colon cancer cell line) using the sulforhodamine B assay. RESULTS: The TPC of extracts varied from 8.2 to 20.3 mg gallic acid equivalents/g dry weight. DPPH radical scavenging effect of extracts decreased in the order of EF > BF > CE > PF > WF, with IC50 values ranging from 74.7 to 680.8 µg/mL. 2,2-azo-bis(3-Ethylbenzothiazoline-6-sulfoic acid) diammonium salt scavenging activity ranged from 0.118 to 0.236 mmol Trolox equivalence/mg extract. The extracts exhibited concentration-dependent reducing power, and EF showed the highest reducing ability. A satisfactory correlation (R(2) > 0.826) between TPC and antioxidant activity was observed. In addition, EF, PF and CE exhibited potent anticancer effects on six cancer cell lines with IC50 values ranging from 40.1 to 166.3 µg/mL. DISCUSSION AND CONCLUSION: The ethanol extract of A. oxyphylla fruit, especially the EF, was found to possess potent antioxidant and anticancer activities, and thus a great potential for the application in food and drug products.

Stability of the recombinant anti­erbB2 scFv­Fc­interleukin­2 fusion protein and its inhibition of HER2­overexpressing tumor cells.

The anti­erbB2 scFv­Fc­IL­2 fusion protein (HFI) is the basis for development of a novel targeted anticancer drug, in particular for the treatment of HER2­positive cancer patients. HFI was fused with the anti­erbB2 antibody and human IL­2 by genetic engineering technology and by antibody targeting characteristics of HFI. IL­2 was recruited to target cells to block HER2 signaling, inhibit or kill tumor cells, improve the immune capacity, reduce the dose of antibody and IL­2 synergy. In order to analyse HFI drug ability, HFI plasmid stability was verified by HFI expression of the trend of volume changes. Additionally, HFI could easily precipitate and had progressive characteristics and thus, the buffer system of the additive phosphate­citric acid buffer, arginine, Triton X­100 or Tween­80, the establishment of a microfiltration, ion exchange, affinity chromatography and gel filtration chromatography­based purification process were explored. HFI samples were obtained according to the requirements of purity, activity and homogeneity. In vivo, HFI significantly delayed HER2 overexpression of non­small cell lung cancer (Calu­3) in human non­small cell lung cancer xenografts in nude mice, and the inhibition rate was more than 60% (P<0.05) in the group treated with 1 mg/kg the HFI dose; HFI significantly inhibited HER2 expression of breast cancer (FVB/neu) transgenic mouse tumor growth in 1 mg/kg of the HFI dose group, and in the following treatment the 400 mm3 tumors disappeared completely. Combined with other HFI test data analysis, HFI not only has good prospects, but also laid the foundation for the development of antibody­cytokine fusion protein­like drugs.

Gas chromatographic-ion trap mass spectrometric analysis of volatile organic compounds by ion-molecule reactions using the electron-deficient reagent ion CCl3(+).

When using tetrachloromethane as the reagent gas in gas chromatography-ion trap mass spectrometry equipped with hybrid ionization source, the cation CCl(3)(+) was generated in high abundance and further gas-phase experiments showed that such an electron-deficient reagent ion CCl(3)(+) could undergo interesting ion-molecule reactions with various volatile organic compounds, which not only present some informative gas-phase reactions, but also facilitate qualitative analysis of diverse volatile compounds by providing unique mass spectral data that are characteristic of particular chemical structures. The ion-molecule reactions of the reagent ion CCl(3)(+) with different types of compounds were studied, and results showed that such reactions could give rise to structurally diagnostic ions, such as [M+CCl(3) - HCl](+) for aromatic hydrocarbons, [M - OH](+) for saturated cyclic ether, ketone, and alcoholic compounds, [M - H](+) ion for monoterpenes, M(·+) for sesquiterpenes, [M - CH(3)CO](+) for esters, as well as the further fragment ions. The mechanisms of ion-molecule reactions of aromatic hydrocarbons, aliphatic ketones and alcoholic compounds with the reagent ion CCl(3)(+) were investigated and proposed according to the information provided by MS/MS experiments and theoretical calculations. Then, this method was applied to study volatile organic compounds in Dendranthema indicum var. aromaticum and 20 compounds, including monoterpenes and their oxygen-containing derivatives, aromatic hydrocarbon and sesquiterpenes were identified using such ion-molecule reactions. This study offers a perspective and an alternative tool for the analysis and identification of various volatile compounds.

The role of the Saccharomyces cerevisiae Cdc7-Dbf4 complex in the replication checkpoint.

The Cdc7-Dbf4 complex is a conserved serine/threonine protein kinase essential for the initiation of eukaryotic DNA replication. Although an mcm5-bob1 mutation bypasses lethality conferred by mutations in CDC7 or DBF4, the Deltacdc7 mcm5-bob1 mutant is sensitive to hydroxyurea (HU), which induces replication stress. To elucidate the reasons for HU sensitivity conferred by deletion of CDC7, we examined the role of Cdc7-Dbf4 in the replication checkpoint. We found that in Cdc7-Dbf4-deficient cells exposed to replication stress, Rad53 remains in a hypophosphorylated form, anaphase spindle is elongated, and checkpoint-specific transcription is not induced. The hypophosphorylated Rad53 exhibits a low autophosphorylation activity, and recombinant Cdc7-Dbf4 phosphorylates Rad53 in vitro. These results suggest that Cdc7-Dbf4 is required for full activation of Rad53 in response to replication stress.

Development of the mesencephalic trigeminal nucleus requires a paired homeodomain transcription factor, Drg11.

The mesencephalic trigeminal nucleus (Me5) innervates muscle spindles and is responsible for receiving and transmitting proprioception from the oro-facial region. Molecular mechanisms underlying the development of the Me5 are poorly understood. Evidence is provided here that transcription factor Drg11 is required for Me5 development. Drg11 was expressed in the Me5 cells of the embryonic and early postnatal mouse brains, and the Me5 cells were absent in Drg11-/- mice at birth. The absence of the Me5 cells in Drg11-/- mice appeared to be caused by increased cell death in the Me5 during embryonic development. In postnatal Drg11-/- mice, Me5 cell innervation of masseter muscle spindles was undetectable, while robust trigeminal motoneuron innervation of masseter muscle fibers was detected. The postnatal body weight of Drg11-/- mice was notably less than that of wild-type mice, and this might result, in part, from disruption of the oro-facial proprioceptive afferent pathway. Taken together, our results demonstrate an essential role for Drg11 in the development of the Me5.

Myosin X regulates netrin receptors and functions in axonal path-finding.

Netrins regulate axon path-finding during development, but the underlying mechanisms are not well understood. Here, we provide evidence for the involvement of the unconventional myosin X (Myo X) in netrin-1 function. We find that Myo X interacts with the netrin receptor deleted in colorectal cancer (DCC) and neogenin, a DCC-related protein. Expression of Myo X redistributes DCC to the cell periphery or to the tips of neurites, whereas its silencing prevents DCC distribution in neurites. Moreover, expression of DCC, but not neogenin, stimulates Myo X-mediated formation and elongation of filopodia, suggesting that Myo X function may be differentially regulated by DCC and neogenin. The involvement of Myo X in netrin-1 function was further supported by the effects of inhibiting Myo X function in neurons. Cortical explants derived from mouse embryos expressing a motor-less Myo X exhibit reduced neurite outgrowth in response to netrin-1 and chick commissural neurons expressing the motor-less Myo X, or in which Myo X is silenced using microRNA (miRNA), show impaired axon projection in vivo. Taken together, these results identify a novel role for Myo X in regulating netrin-1 function.

Two novel O-superfamily conotoxins from Conus vexillum.

O-superfamily conotoxins include several families that have diverse pharmacological activity on Na+, K+ or Ca2+ channels. These superfamily toxins have been mainly found in fish-hunting and mollusk-hunting Conus species. Here, we reported two novel O-superfamily conotoxins, vx6a and vx6b, purified from a worm-hunting cone snail, Conus vexillum. Though their cysteine framework and signal peptides share high similarity with those of other members of O-superfamily, the mature vx6a and vx6b both have a low sequence homology with others. To test the biological function of vx6a, the toxin was chemically synthesized and then tested on the locust dorsal unpaired median (DUM) neuron system which containing various ion channels. Although no any activity on ion channels was found on the DUM neuron system, vx6a could clearly elicit a series of symptoms in mouse via intracranial injection, such as quivering, climbing, scratching, barrel rolling and paralysis of limbs at different dose.

A novel M-superfamily conotoxin with a unique motif from Conus vexillum.

Cone snails are tropical marine mollusks that envenomate prey with a complex mixture of neuropharmacologically active compounds for the purpose of feeding and defence, each evolved to act in a highly specific manner on different parts of the nervous system. Here, we report the peptide purification, molecular cloning, chemical synthesis, and functional characterization of a structurally unique toxin isolated from the venom of Conus vexillum. The novel peptide, designated Vx2, was composed of 21 amino acid residues cross-linked by 3 disulfide bonds (WIDPSHYCCCGGGCTDDCVNC). Intriguingly, its mature peptide sequence shows low level of similarity with other identified conotoxins, and its unique motif (-CCCGGGC-) was not reported in other Conus peptides. However, its signal peptide sequence shares high similarity with those of the M-superfamily conotoxins. Hence, Vx2 could be classified into a new family of the M-superfamily.

A novel conotoxin from Conus striatus, mu-SIIIA, selectively blocking rat tetrodotoxin-resistant sodium channels.

Mu-conotoxin SIIIA, a novel blocker of tetrodotoxin-resistant (TTX-R) voltage-gated sodium channels (VGSCs) has been identified from the fish-hunting cone snail, Conus striatus. The deduced sequence consists of a 20-residue signal peptide, a 31-residue pro-peptide, and a 20-residue mature toxin with its N-terminal Gln cyclized and C-terminus amidated. Mu-SIIIA shares the common cysteine arrangement with other mu-conotoxins. Besides, it exhibits high sequence homology with mu-SmIIIA, a toxin recently characterized from C. stercusmuscarum which potently blocks the TTX-R VGSCs in frog neurons. With whole-cell recording, mu-SIIIA potently and selectively inhibits the TTX-R VGSCs of dissociated adult rat small-diameter dorsal root ganglia (DRG) neurons with a dose- and time-dependent property and irreversibly. Homology-based modeling of mu-PIIIA, SIIIA and SmIIIA implies that they share a common backbone conformation except at the N termini. The hydroxyl-proline residue only present in mu-PIIIA is absent and substituted by an Asp residue in mu-SIIIA and SmIIIA. Similarly, one crucial basic residue (Arg12 in mu-PIIIA) is replaced by serine in the latter two toxins. Such differences might endow them with the capacity to selectively inhibit TTX-S or TTX-R VGSCs. Considering that TTX-R VGSCs predominantly expressed in DRG neurons play pivotal roles in the nociceptive information transmission and that their specific antagonists are still lacking, mu-SIIIA might provide a useful tool for functional studies of these channels, and potentially be developed as an efficient pain killer.

Conus peptides--a rich pharmaceutical treasure.

Marine predatory cone snails (genus Conus) with over 500 species represent what is arguably the largest single genus of marine animals alive today. All Conus are venomous and utilize a complex mixture of Conus peptides to capture their preys and for other biological purposes. Each component of Conus peptides selectively targets a specific subtype of ion channels, neurotransmitter receptors or transporters. Owing to their diversity, more than 50,000 distinct active peptides are theoretically estimated in Conus venoms. These diversified toxins are generally categorized into several superfamilies and/or families based on their characteristic arrangements of cysteine residues and pharmacological actions. Some mechanisms underlying the remarkable diversity of Conus peptides have been postulated: the distinctive gene structure, gene duplication and/or allelic selection, genus speciation, and sophisticated expression pattern and post-translational modification of these peptides. Due to their highly pharmacological potency and target selectivity, Conus peptides have attracted extensive attention with their potentials to be developed as new research tools in neuroscience field and as novel medications in clinic for pain, epilepsy and other neuropathic disorders. Several instructive lessons for our drug development could be also learnt from these neuropharmacological "expertises". Conus peptides comprise a rich resource for neuropharmacologists, and most of them await to be explored.

BmTx3, a scorpion toxin with two putative functional faces separately active on A-type K+ and HERG currents.

A novel HERG channel blocker was isolated from the venom of the scorpion Buthus martensi Karsch, sequenced and characterized at the pharmacological level after chemical synthesis. According to the determined amino acid sequence, the cDNA and genomic genes were then cloned. The genomic gene consists of two exons interrupted by an intron of 65 bp at position -6 upstream from the mature toxin. The protein sequence of this toxin was completely identical with that of a known A-type K+ current blocker BmTx3, belonging to scorpion alpha-KTx subfamily 15. Thus BmTx3 is the first reported alpha-KTx peptide also showing HERG-blocking activity, like gamma-KTx peptides. Moreover, different from classical alpha-KTx peptides, such as charybdotoxin, BmTx3 cannot block Shaker -type K+ channels. Phylogenetic tree analysis reveals that this toxin takes an intermediate position between classical alpha-KTx and gamma-KTx toxins. From a structural point of view, we propose that two separate functional faces might exist on the BmTx3 molecule, responsible for the two different K+-current-blocking functions. Face A, composed of Arg18 and Lys19 in the alpha-helix side, might correspond to HERG blocking activity, whereas Face B, containing a putative functional dyad (Lys27 and Tyr36) in the beta-sheet side, might correspond to A-type blocking activity. A specific deletion mutant with the disrupted Face B, BmTx3-Y36P37del, loses the A-type current-blocking activity, but keeps a similar HERG-blocking activity, as seen with the wild-type toxin.

cDNA cloning of two A-superfamily conotoxins from Conus striatus.

The full-length cDNAs of two A-superfamily conotoxins, kappaA-SIVA and alpha-SII, were respectively cloned and sequenced from Conus striatus using 3' RACE and 5' RACE. The cDNA of kappaA-SIVA encodes a precursor of 68 residues, including a signal peptide of 21 residues, a pro-peptide of 17 residues, and a mature peptide of 30 residues with an additional residue Gly which is prerequisite for the amidation of the preceding C-terminal Cys. The cDNA-deduced sequence of alpha-SII is composed of a signal peptide of 21 residues, a pro-peptide of 29 residues, a mature peptide of 19 residues and three additional residues Arg-Thr-Ile at the C-terminus. This tripeptide might be cleaved off by proteolytic processing. Although these two conotoxins belong to different families and target voltage-gated potassium channel and nicotinic acetylcholine receptor, respectively, they share the same signal sequence, and both are processed at the common signal site -X-Arg- immediately before the mature peptide sequences. The length of 3' untranslational region of alpha-conotoxin SII was extraordinarily large about 10 times longer than that of kappaA-SIVA with 770 and 75 bp, respectively. The elucidated cDNAs of these two toxins will facilitate a better understanding of the process of their post-translational modifications.

[The biological characteristics of SARS virus and its related coronaviruses].

Cases of the life-threatening respiratory disease with no identified cause (designated as "severe acute respiratory syndrome", SARS, in March 2003) were first reported in late 2002 from Guangdong Province, China; they were followed by reports from about other 30 countries (or regions) such as Vietnam, Singapore, Thailand, Hong Kong (China), Canada, and USA etc. Because of its ongoing epidemic and high death rate, SARS has shined an intense spotlight all over the world. The World Health Organization (WHO) has promptly established a network of international laboratories consisting of 13 members around the 10 countries to facilitate the identification of the causative agent of SARS. A novel coronavirus, SARS virus, fulfilling all of Koch's postulates was announced to be the primary aetiological agent of SARS on April 16 by WHO shortly after the Canadian scientists released the full-length genome sequence of SARS virus (Tor2) on April 12. China is now facing a formidable task to fight SARS. In this article, we present a brief summary on the biological characteristics of coronavirus with its associated diseases, and make some suggestions on how to curb this outbreak and how to cure SARS disease based on the potential targets of this novel virus.