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A new cytochalasin, named cytochalasin P1 (1), together with four known analogs (2–5) was isolated from marine-derived fungus Xylaria sp. SOF11 from the South China Sea. The structure of the new compound was elucidated on the basis of MS and NMR (1H, 13C, HSQC, HMBC, and NOESY) data analyses. Compounds 1–5 were tested for their cytotoxicities against four tumor cell lines (SF-268, MCF-7, NCI-H460, and HepG-2). Compounds 1–5 showed significant cytotoxicity against two tumor cell lines MCF-7 and SF-268, with the IC50 values varying between 0.33 and 4.17 μM.

Three new cycloheptapeptides, cordyheptapeptides C-E (1-3), were isolated from the fermentation extract of the marine-derived fungus Acremonium persicinum SCSIO 115. Their planar structures were elucidated on the basis of extensive MS, as well as 1D and 2D (COSY, HMQC, and HMBC) NMR spectroscopic data analyses. The absolute configurations of the amino acid residues were determined by single-crystal X-ray diffraction, Marfey's method, and chiral-phase HPLC analysis. Compounds 1 and 3 displayed cytotoxicity against SF-268, MCF-7, and NCI-H460 tumor cell lines with IC(50) values ranging from 2.5 to 12.1 μM.

The nine-membered indolactam antibiotics belong to a small group of antibiotics showing broad biological activities. However, the in vivo genetic engineering of compounds of this type has not been performed. Here we report the identification of a single gene cluster responsible for the biosynthesis of methylpendolmycin and pendolmycin, two members of this family of antibiotics, from the deep sea bacterium Marinactinospora thermotolerans SCSIO 00652. Bioinformatics analysis and gene inactivation, coupled with metabolite characterization, reveal that MpnB, a nonribosomal peptide synthetase, MpnC, a cytochrome P450, and MpnD, a prenyltransferase, are sufficient to catalyze the biosynthesis of the two antibiotics from L-Ile (or L-Val), L-Trp, and methionine. MpnD is the first identified enzyme that transfers a C5 prenyl unit in a reverse manner to the C-7 position of a Trp-derived natural product.

Three new eremophilane sesquiterpenes (1-3) were isolated from the mangrove endophytic fungus Xylaria sp. BL321 together with 07H239-A (4), a known analogue of the new compounds. The structures of these compounds were elucidated by analysis of their MS, 1D and 2D NMR spectroscopic data. Compound 4 showed activation activity on α-glucosidase at 0.15 μM (146%), and then, 4 gradually produced inhibitory activity on α-glucosidase with increasing concentration, and the IC₅₀ value is 6.54 μM.

Five new C-glycoside angucyclines, named grincamycins B-F (1-5), and a known angucycline antibiotic, grincamycin (6), were isolated from Streptomyces lusitanus SCSIO LR32, an actinomycete of deep sea origin. The structures of these compounds were elucidated on the basis of extensive spectroscopic analyses, including MS and 1D and 2D NMR experiments. All compounds except grincamycin F (5) exhibited in vitro cytotoxicities against the human cancer cell lines HepG2, SW-1990, HeLa, NCI-H460, and MCF-7 and the mouse melanoma cell line B16, with IC₅₀ values ranging from 1.1 to 31 μM.

The tirandamycins (TAMs) are a small group of Streptomyces-derived natural products that target bacterial RNA polymerase. Within the TAM biosynthetic cluster, trdE encodes a glycoside hydrolase whose role in TAM biosynthesis has been undefined until now. We report that in vivo trdE inactivation leads to accumulation of pre-tirandamycin, the earliest intermediate released from its mixed polyketide/nonribosomal peptide biosynthetic assembly line. In vitro and site-directed mutagenesis studies showed that TrdE, a putative glycoside hydrolase, catalyzes in a highly atypical fashion the installation of the Delta(11,12) double bond during TAM biosynthesis.

[Song, Xianqin; Luo, Minghe; Lu, Laichun] Third Mil Med Univ, Coll Pharm, Teaching Expt Ctr, Chongqing 400038, Peoples R China; Qingdao Univ, Affiliated Hosp, Cent Lab, 1677 Wutaishan Rd, Qingdao 266003, Peoples R China; [Huang, Hongbo] Chinese Acad Sci, South China Sea Inst Oceanol, RNAM Ctr Marine Microbiol, CAS Key Lab Trop Marine Bioresources & Ecol,Guand, 164 West Xingang Rd, Guangzhou 510301, Guangdong, Peoples R China

Four new dimeric naphtho-γ-pyrones, named rubasperone D (1), rubasperone E (2), rubasperone F (3), and its atropisomer rubasperone G (4), together with four known monomeric naphtho-γ-pyrones, TMC 256 A1 (5), rubrofusarin B (6), fonsecin (7), and flavasperone (8), were isolated from the mangrove endophytic fungus Aspergillus tubingensis (GX1-5E) cultivated in solid rice medium. Their structures were elucidated by spectroscopic methods, including IR, 1D- and 2D-NMR, and MS. In the in vitro cytotoxicity assays, 5 displayed inhibitory activities against tumor cell lines of MCF-7, MDA-MB-435, Hep3B, Huh7, SNB19, and U87 MG with IC50 values between 19.92 and 47.98 μM. Compounds 1, 6, and 8 also showed mild cytotoxic activity.

Two new cytochalasins, 18-deoxycytochalasin Q (1) and 21-O-deacetylcytochalasin Q (2), together with four known analogues, cytochalasin Q (3), 19,20-epoxycytochalasin Q (4), 21-O-deacetyl-19,20-epoxycytochalasin Q (5), and cytochalasin D (6), were isolated from the fungus Xylaria sp. SCSIO156 originated from the South China Sea marine sediment. The structures of 1 and 2 were elucidated by MS and 1D- and 2D-NMR data analyses, and comparison with known compounds. The known compounds 3–6 were identified by comparison of their MS and NMR data with those reported in the literature. In the in vitro antitumor assay, compounds 2–6 showed mild cytotoxicity against three tumor cell lines (MCF-7, SF-268, and NCI-H460).

Three new bianthraquinone derivatives, alterporriol K (1), L (2) and M (3), along with six known compounds were obtained from extracts of the endophytic fungus Alternaria sp. ZJ9-6B, isolated from the mangrove Aegiceras corniculatum collected in the South China Sea. Their structures were elucidated by one- and two-dimensional NMR spectroscopy, MS data analysis and circular dichroism measurements. Compounds 1, 2 and 3 were first isolated alterporriols with a C-2–C-2′ linkage. The crystallographic data of tetrahydroaltersolanol B (7) was reported for the first time. In the primary bioassays, alterporriol K and L exhibited moderate cytotoxic activity towards MDA-MB-435 and MCF-7 cells with IC50 values ranging from 13.1 to 29.1 µM.

Tirandamycins are bacterial RNA polymerase inhibitors holding great potential for antibacterial agent design. To elucidate the biosynthetic machinery and generate new derivatives, the tirandamycin biosynthetic gene cluster was cloned and sequenced from marine-derived Streptomyces sp. SCSIO1666. The biosynthetic gene cluster of tirandamycin spans a DNA region of ∼56kb and consists of 15 open reading frames (ORFs) which encode three type I polyketide synthases (TrdAI, AII, AIII), one non-ribosomal peptide synthetase (TrdD), one phosphopantetheinyl transferase (TrdM), one Type II thioesterase (TrdB), one FAD-dependent oxidoreductase (TrdL), one cytochrome P450 monooxygenase (TrdI), three proteins related to resistance and regulations (TrdHJK), and four proteins with unknown function (TrdCEFG). To investigate the roles of the genes played in the biosynthetic machinery, seven genes (trdAI and trdBDFHIK) were inactivated via in frame replacement with an apramycin gene cassette using λ-RED recombination technology. The ΔtrdAI and ΔtrdD mutants targeting the ketosynthase and adenylation domain of TrdAI and TrdD, respectively, abolished the production of tirandamycins, confirming their involvement in the tirandamycin biosynthesis. TrdH showed high homology to LuxR family transcriptional regulatory proteins, disruption of which abolished the production of tirandamycins, indicating that TrdH is a positive regulator for tirandamycin biosynthesis. On the other hand, TrdK showed high homology to TetR-family transcriptional regulatory proteins, disruption of which significantly increased the yields of tirandamycins almost one-fold, implicating that TrdK is a negative regulator for tirandamycin biosynthesis. Disruption of the gene trdI resulted in the accumulation of the intermediate tirandamycin C (3) and a trace amount of new product tirandamycin C2 (5). A model of tirandamycin biosynthesis was proposed based on bioinformatics analyses, gene inactivation experiments and intermediates isolated from the mutants. These findings set the stage for further study of the tirandamycin biosynthetic mechanism and rationally engineer new tirandamycin analogues.

Three new dimeric naphtho- γ-pyrones, named rubasperone A ( 1), rubasperone B ( 2), and rubasperone C ( 3), together with two known compounds, rubrofusarin ( 4) and rubrofusarin B ( 5), were isolated from the mangrove endophytic fungus ASPERGILLUS TUBINGENSIS (GX1-5E). Their structures were determined by spectroscopic methods, including IR, MS, and 1D and 2D NMR. The structures of 1 and 2 were further confirmed by X-ray crystallography. In the bioactivity assays against tyrosinase and α-glucosidase, rubrofusarin ( 4) exhibited moderate tyrosinase inhibitory activity, with an IC 50 value of 65.6 μM, and rubasperone C ( 3) showed mild α-glucosidase inhibitory activity, with an IC 50 value of 97.3 μM.

A mild hydrothermal process to prepare Ba2SbLnO6 (Ln = Pr, Nd, Sm, Eu) perovskite-type oxides are presented. These perovskites were characterized on the basis of X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), inductively-coupled plasma spectra (ICP) techniques. Primary structure was confirmed using Rietveld method based on XRD data shows that the likely space groups of Ba2SbLnO6 are R-3 for Ln = Pr and Nd and Fm-3m for Ln = Sm and Eu, respectively. The measurement of Mossbauer effect of the 37.2 keV γ transition of 121Sb indicates that the isomer shift of these perovskites falls in the region of the Sb5+ and reflects some hybridized-orbital behavior in Sb–O bonds.

Topological phononic insulators (TPnIs) show promise for application in the manipulation of acoustic waves for the design of low-loss transmission and perfectly integrated communication devices. Since solid phononic crystals exist as a transverse polarization mode and a mixed longitudinal-transverse polarization mode, the realization of topological edge states for both out-of-plane and in-plane bulk elastic waves is desirable to enhance the controllability of the edge waves in solid systems. In this paper, a two-dimensional (2D) solid/solid hexagonal-latticed phononic system that simultaneously supports the topologically protected edge states for out-of-plane and in-plane bulk elastic waves is investigated. Firstly, two pairs of two-fold Dirac cones, respectively corresponding to the out-of-plane and in-plane waves, are obtained at the same frequency by tuning the crystal parameters. Then, a strategy of zone folding is invoked to form double Dirac cones. By shrinking and expanding the steel scatterer, the lattice symmetry is broken, and band inversions induced, giving rise to an intriguing topological phase transition. Finally, the topologically protected edge states for both out-of-plane and in-plane bulk elastic waves, which can be simultaneously located at the frequency range from 1.223 to 1.251 MHz, are numerically observed. Robust pseudospin-dependent elastic edge wave propagation along arbitrary paths is further demonstrated. Our results will significantly broaden its practical application in the engineering field.

In this paper, the metal aluminum oxide ceramic nanotubes (M–Al–O, M = Zn, Mg and Ba) were synthesized by the use of porous anodic aluminum oxide (AAO) template. Metal oxide nanotubes were firstly formed from the thermal decomposition of respective nitrates within the pores of AAO templates. Then M–Al–O nanotubes were synthesized through the solid-state chemical reaction between the metal oxide nanotubes and AAO. TEM observation shows that the as-prepared samples are nanotubes and XRD measurement reveals that M–Al–O nanotubes (M = Zn, Mg and Ba) are crystalline in nature with spinel structure.

In this study, we have investigated effective refractive index (ERI) and power confinement factor (PCF) in single nanobelt and coupling between two parallel nanobelts using finite-difference time-domain (FDTD) method. As the width of nanobelt increases, both the effective refractive index (ERI) and power confinement factor (PCF) are increased till the saturation values. The ERI changes linearly with refractive index in our simulation range, while the PCF shows nonlinear characteristic. The coupling length ( L T ) between two nanobelts is much shorter than that in weakly coupled waveguide, which may find applications in solving the cross talk problem. Nanobelt behaves like slab waveguide when the width becomes big enough.

We have successfully fabricated ferrimagnetic bulk Mn4N by doping bulk Mn metal with nitrogen at 900 °C in a flow of NH3/N2 mixture gas. The X-ray diffraction pattern of bulk Mn4N shows a pure Mn4N phase. By magnetic measurements using VSM and SQUID, the hysteresis loop of the bulk Mn4N at 5 and 300 K, together with the M–T curve from 2 to 1000 K at 2 kOe external field is measured. From the 1/χ–T curve, it can be concluded that the sample is ferrimagnet with its Curie temperature around 740 K. The magnetic moment is calculated to be about 0.88 μB/cell at 5 K. The microwave characteristic was investigated by the vector network analyzer in the frequency from 2 to 12 GHz and was fitted by the transmission line theory. We have given the calculated results for the sample thickness of 1.4, 1.5 and 1.9 mm, respectively, by using the electromagnetic parameters of the Mn4N composite. The loss peak shifts to lower frequency with the increasing of composite thickness.

Magnetoelectric CoFe2O4/Pb(Zr0.52Ti0.48)O3 composite nanotubes with diameters about 80 and 300 nm, and the length about 100 μm, were prepared by sol–gel template method. The studies with transmission electron microscopy (TEM) revealed that the composite material is characterized by the tubular microstructure; and X-ray diffraction (XRD) and selected area electron diffraction (SAED) patterns showed the coexistence of spinel CoFe2O4 (CFO) and perovskite Pb(Zr0.52Ti0.48)O3 (PZT) phases in the composite (CFO/PZT) nanotubes. Magnetic property of the CFO/PZT composite nanotubes was similar to pure CFO nanotubes. Also, the composite nanotubes exhibited ferroelectricity, which was just the same as the pure PZT nanotubes.

Single-crystalline layered SnO2 microrods were synthesized by a simple tin?water reaction at 900??C. The structural and optical properties of the sample were characterized by x-ray powder diffraction, energy-dispersive x-ray spectroscopy, scanning electron microscopy, high resolution transmission electron microscopy, Raman scattering and photoluminescence (PL) spectroscopy. High resolution transmission electron microscopy studies and selected area electron diffraction patterns revealed that the layered SnO2 microrods are single crystalline and their growth direction is along [1 1 0]. The growth mechanism of the microrods was proposed based on SEM, TEM characterization and thermodynamic analysis. It is deduced that the layered microrods grow by the stacking of SnO2 sheets with a (1?1?0) surface in a vapour?liquid?solid process. Three emission peaks at 523, 569 and 626?nm were detected in room-temperature PL measurements.

Enhanced photoluminescence (PL) phenomena have been observed at the ends/junctions of the hexagonal ZnO micro-rods prepared from zinc grains by the thermal evaporation method. In order to study the origin of the phenomena, finite difference time domain (FDTD) method was employed here for simulation. This enhanced PL was analysed to be attributed to the waveguide effect, and a good agreement with the enhanced PL phenomena was obtained.

The in vivo binding analysis of vesicular monoamine transporter type 2 (VMAT2) to radioligand has provided a means of investigating related disorders. Anesthesia is often inevitable when the investigations are performed in animals. In the present study, we tested effects of four commonly-used anesthetics: isoflurane, pentobarbital, chloral hydrate and ketamine, on in vivo VMAT2 binding to (18)F-FP-(+)-DTBZ, a specific VMAT2 radioligand, in rat brain.The transient equilibrium time window for in vivo binding of (18)F-FP-(+)-DTBZ after a bolus injection was firstly determined. The brain biodistribution studies under anesthetized and awake rats were then performed at the equilibrium time. Standard uptake values (SUVs) of the interest brain regions: the striatum (ST), hippocampus (HP), cortex (CX) and cerebellum (CB) were obtained; and ratios of tissue to cerebellum were calculated.Isoflurane and pentobarbital did not alter distribution of (18)F-FP-(+)-DTBZ in the brain relative to the awake group; neither SUVs nor ratios of ST/CB and HP/CB were altered significantly. Chloral hydrate significantly increased SUVs of all the brain regions, but did not significantly alter ratios of ST/CB and HP/CB. Ketamine significantly increased SUVs of the striatum, hippocampus and cortex, and insignificantly increased the SUV of the cerebellum; consequently, ketamine significantly increased ratios of ST/CB and HP/CB.It is concluded that in vivo VMAT2 binding to (18)F-FP-(+)-DTBZ are not altered by isoflurane and pentobarbital, but altered by chloral hydrate and ketamine. Isoflurane and pentobarbital may be promising anesthetic compounds for investigating in vivo VMAT2 binding. Further studies are warranted to investigate the interactions of anesthetics with VMAT2 binding potential with in vivo PET studies.

A new diketopiperazine (DKP) derivative, (6R,3Z)-3-benzylidene-6-isobutyl-1-methyl piperazine-2,5-dione (1), as well as five known DKPs 2–6 was isolated from a deep sea-derived Streptomyces sp. SCSIO 04496. The structure of 1 was elucidated using a combination of 1D and 2D NMR, HR-ESI-MS and chiral-phase HPLC techniques. Compounds 1–6 did not show cytotoxic activity at a concentration of 100 μM in bioactivity assay.

Face recognition in unconstrained environments is often influenced by pose variations. And the problem is basically the identification that uses partial data. In this paper, a method fusing structure and texture information is proposed to solve the problem. In the register phase, the approximate 180 degree information of face is acquired, and the data used to identify individual is obtained from a random single view. Pure face is extracted from 3D data first, then convert the original data to the form of spherical depth map (SDM) and spherical texture map (STM), which are invariant to out-plane rotation, subsequently facilitating the successive alignment-free identification that is robust to pose variations. We make identification through sparse representation for its well performance with the two maps. Experiments show that our proposed method gets a high recognition rate with pose and expression variations.

As for the safety of mobile objects when traversing through a sensory field, a new exposure model based on voronoi diagram is proposed, and furthermore, a new heuristic anti- monitoring method for moving objects is designed to find a safe path with the minimum risk when the mobile objects are traversing through the sensory field. Theoretical analysis and simulation results show that, the newly proposed method can achieve satisfying anti-monitoring performance and can select a path with minimum risk for mobile objects to traverse through the sensory field.

A sol?gel method followed by a hydrogen reduction procedure was proposed in this work for the preparation of metal nanotubes. The tube length, diameter, wall thickness and, most importantly, the chemical components can be adjusted conveniently. Several examples of metal nanotubes (Fe, Ni, Pb and CoFe) were prepared by using anodic aluminium oxide (AAO) templates. The fabricated nanotubes are uniform in diameter and wall thickness through the entire tubes. The length of the nanotubes is about 100??m, with an aspect ratio of about 1000.

Rutile phase SnO 2 microtubes were successfully synthesized using a thermal evaporation method at 1550 °C. The products were characterized by X-ray diffraction, scanning electron microscopy and micro-Raman scattering. The microtubes are as long as about 1 mm with almost perfect rectangular cross-section. They possess a large cavity channel of about 30 μm in width and four smooth side surfaces. The side surfaces of SnO 2 microtubes are (1 1 0) and ( 1 1 ¯ 0 ) planes, while their tube axes are [0 0 1]. The possible formation mechanism of the rectangular SnO 2 microtubes is presented.

The Mossbauer effect has been applied to a wide variety of objects related to Chinese archaeology. Besides ceramic artifacts, materials like porcelain, glazes, bronzes, ancient coins, ancient mineral drugs, and even fossils were studied. This article reviews these applications with particular emphasis on the study of the famous terracotta warriors and horses of the Qin Dynasty.

The study for exotic topological effects of sound has attracted uprising interests in fundamental physics and practical applications. Based on the concept of valley pseudospin, we demonstrate the topological valley transport of plate-mode waves in a homogenous thin plate with periodic stubbed surface, where a deterministic two-fold Dirac degeneracy is form by two plate modes. We show that the topological property can be controlled by the height of stubs deposited on the plate. By adjusting the relative heights of adjacent stubs, the valley vortex chirality and band inversion are induced, giving rise to a phononic analog of valley Hall phase transition. We further numerically demonstrate the valley states of plate-mode waves with robust topological protection. Our results provide a new route to design unconventional elastic topological insulators and will significantly broaden its practical application in the engineering field.

In this paper, we realize the topological edge modes of a shear horizontal (SH) guided wave in the one-dimensional (1D) composite structure that exist at the phononic band gaps opened at the center of the Brillouin zone (BZ), or at the zone boundary, or both. Furthermore, we investigate the topological edge modes in periodic acoustic systems result from both Bragg scattering and local resonances. In particular, we find and demonstrate that, in our system where topological and trivial defect states coexist, these results provide a new paradigm for manipulating the existence of the interface states in a set of prescribed band gaps that can have potential applications in the design of novel acoustic devices.

In this manuscript, we report the first successful epitaxial growth of ZnO nanowires on ZnS nanobelts via the metal organic chemical vapor deposition (MOCVD) method. The compositional and structural analyses show that the product consists of wurtzite-structured ZnS/ZnO nanobelt/nanowire heterostructures, which have an epitaxial relationship with identical orientation along the (100) and (002) planes, respectively. Single crystallinity, the same orientation between the ZnS and ZnO, and a short growth time make the new epitaxial growth method with the pre-prepared nanostructures as substrates appropriate for the construction and investigation of one-dimensional heterostructures.

Asperterpenoid A (I) exhibits strong inhibitory activity against the title phosphatase (mPTPB) with an IC50 value of 2.2 μM.

Three genes, mcbABC, that drive the biosynthesis of marinacarbolines, have been elucidated through genome mining, gene inactivation, heterologous expression, feeding, and site-directed mutagenesis experiments. McbB is highlighted as a novel enzyme for the β-carboline core construction, which involves a Pictet-Spengler cyclization process and requiring E97 for biochemical activity.

03219A (1), a new pregnene steroid possessing a rare Δ(8,9)-double bond in the skeleton, together with the known naphthoquinone antibiotic (+)-cryptosporin (2) have been isolated from the fermentation broth of Streptomyces sp. SCSIO 03219, which was isolated from a marine sediment collected in the South China Sea. The structure of 03219A was elucidated using a combination of NMR, MS and X-ray crystallographic methods.

9-Methylstreptimidone is a glutarimide antibiotic showing antiviral, antifungal, and antitumor activities. Genome scanning, bioinformatics analysis, and gene inactivation experiments reveal a gene cluster responsible for the biosynthesis of 9-methylstreptimidone in Streptomyces himastatinicus. The unveiled machinery features both acyltransferase- and thioesterase-less iterative use of module 5 as well as a branching module for glutarimide generation. Impressively, inactivation of smdK leads to a new carboxylate analogue unveiling a new mechanism for polyketide terminal diene formation.

Asperterpenoid A (1), a novel sesterterpenoid with a new carbon skeleton, has been isolated from a mangrove endophytic fungus Aspergillus sp. 16-5c. Its structure was characterized by extensive spectroscopic methods, and the absolute configuration was determined by single crystal X-ray diffraction analysis. Asperterpenoid A (1) exhibited strong inhibitory activity against Mycobacterium tuberculosis protein tyrosine phosphatase B (mPTPB) with an IC(50) value of 2.2 μM.

Griseoviridin (GV) and viridogrisein (VG, also referred to as etamycin), produced by Streptomyces griseoviridis, are two chemically unrelated compounds belonging to the streptogramin family. Both of these natural products demonstrate broad-spectrum antibacterial activity and constitute excellent candidates for future drug development. To elucidate the biosynthetic machinery associated with production of these two unique antibiotics, the gene cluster responsible for both GV and VG production was identified within the Streptomyces griseoviridis genome and characterized, and its function in GV and VG biosynthesis was confirmed by inactivation of 30 genes and complementation experiments. This sgv gene cluster is localized to a 105 kb DNA region that consists of 36 open reading frames (ORFs), including four nonribosomal peptide synthetases (NRPSs) for VG biosynthesis and a set of hybrid polyketide synthases (PKS)-NRPSs with a discrete acyltransferase (AT), SgvQ, to assemble the GV backbone. The enzyme encoding genes for VG versus GV biosynthesis are separated into distinct "halves" of the cluster. A series of four genes: sgvA, sgvB, sgvC, and sgvK, were found downstream of the PKS-NRPS; these likely code for construction of a γ-butyrolactone (GBL)-like molecule. GBLs and the corresponding GBL receptor systems are the highest ranked regulators that are able to coordinate the two streptomyces antibiotic regulatory protein (SARP) family positive regulators SgvR2 and SgvR3; both are key biosynthetic activators. Models of GV, VG, and GBL biosynthesis were proposed by using functional gene assignments, determined on the basis of bioinformatics analysis and further supported by in vivo gene inactivation experiments. Overall, this work provides new insights into the biosyntheses of the GV and VG streptogramins that are potentially applicable to a host of combinatorial biosynthetic scenarios.

Marinactinospora thermotolerans SCSIO 00652, originating from a deep-sea marine sediment of the South China Sea, was discovered to produce antimicrobial nucleoside antibiotic A201A. Whole-genome scanning and annotation strategies enabled us to localize the genes responsible for A201A biosynthesis and to experimentally identify the gene cluster; inactivation of mtdF , an oxidoreductase gene within the suspected gene cluster, abolished A201A production. Bioinformatics analysis revealed that a gene designated mtdA furthest upstream within the A201A biosynthetic gene cluster encodes a GntR family transcriptional regulator. To determine the role of MtdA in regulating A201A production, the mtdA gene was inactivated in frame and the resulting Δ mtdA mutant was fermented alongside the wild-type strain as a control. High-performance liquid chromatography (HPLC) analyses of fermentation extracts revealed that the Δ mtdA mutant produced A201A in a yield ∼25-fold superior to that of the wild-type strain, thereby demonstrating that MtdA is a negative transcriptional regulator governing A201A biosynthesis. By virtue of its high production capacity, the Δ mtdA mutant constitutes an ideal host for the efficient large-scale production of A201A. These results validate M. thermotolerans as an emerging source of antibacterial agents and highlight the efficiency of metabolic engineering for antibiotic titer improvement.

To investigate the surgical technique and short-term effectiveness of anterior cruciate ligament (ACL) reconstruction with LARS artificial ligament.Between November 2008 and April 2010, eighty patients with ACL injury were treated with LARS artificial ligament under arthroscope and successfully followed up. There were 51 males and 29 females, aged from 17 to 43 years with an average of 29.2 years. The injuries were caused by sport in 63 cases, traffic accident in 14 cases, and bruise in 3 cases. There were 43 left knees and 37 right knees. The disease duration ranged from 10 days to 11 months. The anterior drawer test, Lachman test, and pivot shift test for all cases were rated as positive. The preoperative Lysholm score was 55.4 +/- 5.7, Irgang score was 48.3 +/- 6.2, and Larson score was 54.8 +/- 7.4; and the International Knee Documentation Committee (IKDC) score was lower than normal level in all cases. Oblique coronal MRI showed ACL injury in all cases. Residual ACL and synovium were preserved during surgery.All incisions healed by first intention without complication of infection or deep venous thrombosis. All patients were followed up 7 to 24 months with an average of 16.8 months. There were 3 cases of screws exposure toward femoral cortical bone, 2 cases of loosening tibial screw, and 1 case of knee extension limitation, and they were cured after symptomatic treatment. No LARS artificial ligament rupture and joint fibrosis occurred during follow-up. At last follow-up, the results of anterior drawer test, Lachman test, and pivot shift test were positive in 2, 3, and 3 patients, respectively. There were significant differences in Lysholm, Irgang, and Larson scores of affected knees between preoperation and 6 weeks postoperatively, last follow-up, respectively (P0.05). The normal rate of IKDC score were 43.75% (35/80) and 97.50% (78/80) at 6 weeks postoperatively and last follow-up, respectively.The viscoelastic properties of LARS artificial ligament is different from that of biological materials. The graft should be fixed at a relatively extension position to avoid knee extension limitation and slight loosening of graft tension is permitted at flexion position. Good clinical result could be achieved if the technique is well applied.

Four new norsesquiterpene peroxides, named talaperoxides A-D (1-4), as well as one known analogue, steperoxide B (5, or merulin A), have been isolated from a mangrove endophytic fungus, Talaromyces flavus. Their structures were elucidated mainly by 1D and 2D NMR. Structures of 1, 2, and 5 were further confirmed by single-crystal X-ray diffraction, and their absolute configurations were also determined using copper radiation. Cytotoxic activities of compounds 1-5 were evaluated in vitro against human cancer cell lines MCF-7, MDA-MB-435, HepG2, HeLa, and PC-3. Compounds 2 and 4 showed cytotoxicity against the five human cancer cell lines with IC50 values between 0.70 and 2.78 μg/mL.

Eight secondary metabolites, including three new azaphilones (chermesinones A-C, 1-3), three new p-terphenyls (6'-O-desmethylterphenyllin, 4; 3-hydroxy-6'-O-desmethylterphenyllin, 5; 3''-deoxy-6'-O-desmethylcandidusin B, 7), and two known p-terphenyls (6, 8), were isolated from the culture of the mangrove endophytic fungus Penicillium chermesinum (ZH4-E2). Their structures were established by spectroscopic analysis. The absolute configuration of 1 was determined by X-ray crystallography. Terphenyls 4, 5, and 6 exhibited strong inhibitory effects against α-glucosidase with IC50 values of 0.9, 4.9, and 2.5 μM, respectively. Terphenyls 7 and 8 showed inhibitory activity toward acetylcholinesterase with IC50 values of 7.8 and 5.2 μM.