Distinct Characteristics of Bacterial Community in the Soil of Nanshazhou Island, South China Sea.

Characterizing soil bacterial community is important to understand microbial distribution affected by environmental factors. Here, we investigated the bacterial communities distributed from different location on Nanshazhou island, South China Sea. We collected and compared soil bacterial communities from central island, intertidal island, and inshore island. Results showed no difference in the bacterial richness and diversity for the soils from the three different locations. However, weighted and unweighted UniFrac distances analysis revealed that the three soil samples were clearly separated from each other. Five bacterial phyla, including Proteobacteria, Bacteroidetes, Verrucomicrobia, Spirochaetes and Tenericutes were more abundant in the inshore island sample; while Deinococcus-Thermus was more abundant in the intertidal island sample; and the central island sample had more abundant Gemmatimonadetes and Planctomycetes. Bacterial structure showed significantly positive relationships with organic matter content, but it was significantly negatively correlated with sodium content. Furthermore, a network analysis based on Spearman correlation coefficients showed that there were similar numbers of positive and negative correlations within the bacterial community of Nanshazhou island. Our results revealed that the soil bacterial communities in the three sampling sites were easily affected by environmental fluctuations.

A chloroplast-inspired nanoplatform for targeting cancer and synergistic photodynamic/photothermal therapy.

Specific targeting capabilities and effective phototherapeutic functions are the key demands for precise cancer phototherapeutic agents. Herein, a bioinspired nanoplatform composed of Cu(ii)-chlorophyll-hyaluronic acid nanoparticles (Cu(ii)Chl-HA NPs) was developed for targeting cancer and synergistic photodynamic/photothermal therapy. Inspired by the photonic biosystem of the chloroplast, Cu(ii) chlorophyll was used as a photosensitive substituent to covalently connect with a hydrophilic HA tail rather than a natural phytol tail, and this conjugate further assembled into a nanoparticle-like morphology under non-covalent interaction. Time-dependent density functional theory calculations reveal that the Cu(ii) chlorophyll has a much smaller energy gap between an excited singlet and excited triplet, and theoretically leads to rapid electron intersystem crossing that would benefit the PDT effect. In addition, a series of experiments have proven that, under 650 nm laser irradiation, the nanoplatform of Cu(ii)Chl-HA can produce a high amount of singlet oxygen and exhibit an outstanding photothermal conversion capability. More interestingly, owing to the specific interactions between the HA component and the CD44 receptor on the cell membrane, the HA tails impart Cu(ii)Chl-HA NPs an excellent receptor-mediated targeting performance toward CD44-overexpressing cancer cells. Based on these features, the nanoplatform of Cu(ii)Chl-HA NPs presents active targeting and outstanding dual modality synergistic PDT/PTT performance of cancer both in vitro and in vivo. Thus, this work opens up a new strategy to fabricate a bioinspired multifunctional cancer phototherapy nanoplatform.

A study of genotoxicity and oxidative stress induced by mercuric chloride in the marine polychaete Perinereis aibuhitensis.

The marine polychaete worm Perinereis aibuhitensis was used to study the genotoxic effects of mercuric chloride by means of the comet assay and micronucleus (MN) test. P. aibuhitensis was subjected in vivo to two different concentrations of mercuric chloride (0.05mgL-1 and 0.5mgL-1) for 96h. The comet assay of coelomocytes demonstrated that TailDNA% values increased with extended exposure to or increased concentrations of HgCl2 (p<0.01). The frequency of MNs was the highest in the treatment with 96h of exposure at all concentrations (p<0.01). The genotoxic effect of HgCl2 was both dose- and time-dependent in exposed P. aibuhitensis. The activities of the antioxidant enzymes, superoxide dismutase (SOD) and glutathione peroxidases (GPx) were also estimated. Significant variations in antioxidant enzyme activities depended on the sampling time and the concentrations of mercuric chloride. Compared with the control, the activities of the antioxidant enzymes (SOD and GPx) were elevated at the lower concentration of mercuric chloride (0.05mg L-1) (p<0.05) for shorter exposure periods (24h and 72h). At the higher concentration of mercury (0.5mgL-1), the activities of GPx and SOD were inhibited; no variation was observed. These results proved that the use of the comet assay and MN test in coelomocytes of P. aibuhitensis is appropriate for determining the levels of DNA damage and that P. aibuhitensis is a species that is sensitive to mercury pollutants. This species may be considered a suitable candidate for monitoring marine heavy metal pollution.

Dichloridobis[ethyl 2-(2-amino-1,3-thia-zol-4-yl)acetate-κ(2)O,N(3)]cadmium.

The asymmetric unit of the title compound, [CdCl(2)(C(7)H(10)N(2)O(2)S)(2)], contains two complex molecules with similar configurations. The Cd(II) atoms are each six-coordinated by two thiazole N and two carbonyl O atoms from the 2-(2-amino-1,3-thiazol-4-yl)acetate ligand, and by two Cl(-) anions in a distorted octa-hedral geometry. In the crystal, intra- and inter-molecular N-H⋯Cl hydrogen bonds create parallel chains along [1-10]. C-H⋯Cl inter-actions also occur.

A modified protocol for the comet assay allowing the processing of multiple samples.

In the present study, we developed a modified protocol for the basic comet assay that increased efficiency without sacrificing assay reliability. A spreader was used to spread agarose-embedded cells on a slide, making the manipulation and processing of multiple samples easier. Using this technique, we are able to rapidly prepare five or more comet assay samples on one slide. To demonstrate the effect of the protocol modifications on assay reliability, we present an example of how the comet assay was used in our laboratory to analyze the effect of melatonin (N-acetyl-5-methoxitryptamine; MEL) on the DNA repair ability of Gentiana macrophylla Pall. protoplasts after irradiation with different doses of ultraviolet-B radiation. A slight, but statistically significant (P<0.01), dose-related protective effect of MEL was observed in our experiments. The first use of the comet assay was to confirm the antioxidant and DNA repair functions of MEL in plants. The modified protocol is cost-effective and provides substantial advantages over the conventional comet assay.

A mild phosphine-free synthesis of alkylamine-capped CdSe nanocrystals.

A new phosphine-free approach has been developed to synthesize high-quality cadmium selenide (CdSe) nanocrystals with cubic zinc-blende structure, by using the highly reactive selenium (Se) precursor at milder temperature than that used in the traditional phosphine route. This Se precursor was obtained from the reduction of Se powder by sodium borohydride in N,N-dimetbylformamide, in the absence of phosphine. Without the addition of other long-chain coordinating substances in this approach, the alkylamines such as dodecylamine (DDA) and octylamine (OA) were used as reaction solvents, and they also acted as surface capping reagents to produce DDA-capped and OA-capped CdSe NCs, respectively. The rapid nucleation and slow growth were observed by ultraviolet-visible absorption spectrum. The resulting OA-capped CdSe NCs grew faster compared with DDA-capped CdSe NCs under the same other conditions. These as-synthesized CdSe nanocrystals showed relatively narrow size distribution and high photoluminescence quantum efficiency (up to 9.4% for OA-capped CdSe NCs). This mild approach is low cost, relatively low danger and high production yield (approximately 80%), indicating that it is very effective for the phosphine-free synthesis of alkylamine-capped CdSe nanocrystals.

Hot-injection synthesis of highly luminescent and monodisperse CdS nanocrystals using thioacetamide and cadmium source with proper reactivity.

Thioacetamide (TAA) has served as an excellent sulfur source to react with cadmium stearate to controllably produce highly luminescent and monodisperse CdS nanocrystals through the hot-injection method in dodecylamine solvent. The kinetics and thermodynamics of nucleation/growth of CdS nanocrystals, as well as their optical properties are controlled by changing synthesis conditions such as reaction time, injection/growth temperatures, TAA concentration and cadmium source with different reactivity. Temperature-dependent release of reactive sulfur species from TAA, together with proper reactivity of cadmium source, facilitates the better separation of nucleation and growth stage, the formation of highly monodisperse CdS nanocrystals with tunable size and further self-assembly into ordered superlattices. When cadmium carboxylates such as cadmium stearate and cadmium oleate are used as cadmium sources, surface trap emission of CdS nanocrystals can be gradually removed to obtain bright pure-blue emission with increasing reaction time. The highest quantum efficiency of up to 33.6% is achieved when using cadmium stearate as cadmium source at the injection/growth temperatures of 230/210 degrees C for 90min.

4,4'-Bipyridinium bis-(oxalato-κO,O)cuprate(II): an ion-pair complex.

The title compound, (C(10)H(10)N(2))[Cu(C(2)O(4))(2)] or (4,4'-H(2)bpy)[Cu(ox)(2)] (bpy is 4,4'-bipyridine and ox is oxalate), is an ion-pair complex comprising a protonated 4,4'-bipyridinium dication and a square-planar dioxalatocopper(II) dianion. In the centrosymmetric dianion, the Cu(II) centre is coordinated by four O atoms from the two dicrete oxalate ligands [Cu-O = 1.9245 (19) and 1.9252 (17) Å], while the planar dications are also centrosymmetric. Inter-species N-H⋯O hydrogen bonds link the cations and anions into one-dimensional chains and, together with weak intra-ion C-H⋯O inter-actions, give a two-dimensional sheet structure.

Bis(2-amino-thia-zole-4-acetato)aquazinc(II).

In the title compound, [Zn(C(5)H(5)N(2)O(2)S)(2)(H(2)O)], the central Zn atom (2 site symmetry) is five-coordinated by two N and three O atoms [Zn-N = 2.047 (3) Å, Zn-O = 2.099 (2) and 1.974 (4) Å] in a distorted square-pyramidal geometry. Besides one O atom from a water mol-ecule, two 2-amino-thia-zole-4-acetate ligands provide two N and two O atoms as coordinated atoms. In the crystal structure, inter-molecular O-H⋯O and N-H⋯O hydrogen bonds connect the mol-ecules into an infinite three-dimensional framework.

[Anassociation study between OPHN1 gene rs492933 polymorphism and mental retardation in children of the Qinba Mountain region.].

The OPHN1 gene encodes a Rho-GTPase activating protein (RhoGAP), and mutations in OPHN1 are responsible for non-specific X-linked mental retardation (NSMR). A SNP located in the 5'-untranslated region (UTRs) of OPHN1 (rs492933) was examined by PCR-RFLP to assess its contribution to cognitive ability in 234 unrelated healthy and MR children in the Qinba Mountain region in Shaanxi. The allelic frequencies of rs492933 were 0.826 for the C allele and 0.174 for the T allele. Genotype frequencies and allelic frequencies were not significantly different between the MR and the controls, or between the borderline group and the controls. In conclusion, there is no association between the OPHN1 gene polymorphism and NSMR in the Qinba Mountain region children.

Bis(2-amino-4-methyl-1,3-thia-zole-κN)dichloridocadmium(II).

In the title compound, [CdCl(2)(C(4)H(6)N(2)S)(2)], the Cd(II) atom is coordinated by two chlorido ligands and two N atoms of the 2-amino-5-methyl-1,3-thia-zole (amtz) ligands in a slightly distorted tetra-hedral coordination geometry. Intra- and inter-molecular N-H⋯Cl hydrogen bonding stabilizes the crystal structure. A weak S⋯Cl inter-action [3.533 (2) Å] is observed between neighboring mol-ecules.

Bis(ethyl 2-amino-4-thia-zoleacetato-κN)silver(I) nitrate.

In the title complex, [Ag(C(7)H(10)N(2)O(2)S)(2)]NO(3), the Ag(I) cation is bicoordinated in an almost linear configuration by two N-donor atoms of the thia-zole rings of two distinct ethyl 2-amino-4-thia-zoleacetate (EATA) ligands. The dihedral angle between the two thia-zole rings is 49.9°. A weak Ag⋯O (2.729 Å) inter-action between the Ag cation and one of the O atoms from the nitrate anion is observed, and a pseudo-dimer is formed through a weak Ag⋯S (3.490 Å) inter-action between the Ag cation and the S atom of the thia-zole ring of a symmetry-related mol-ecule. In the crystal structure, there are intra- and inter-molecular N-H⋯O hydrogen bonds. The occurrence of inter-molecular N-H⋯O hydrogen bonds results in the formation of two-dimensional sheets parallel to (010), which are further linked into a three-dimensional network through weak C-H⋯O inter-actions.

Determination of 6-mercaptopurine based on the fluorescence enhancement of Au nanoparticles.

A novel method for the determination of 6-mercaptopurine (6MP) has been developed based on fluorescence enhancement of Au nanoparticles (AuNPs). The fluorescent AuNPs with mean diameter of approximately 15 nm were synthesized in aqueous solution, exhibiting the stable maximum emission at 367 nm, under the excitation at wavelength of 264 nm. The AuNPs self-assembly with 6MP were characterized with transmission electron microscopy (TEM), ultraviolet-visible (UV-vis) absorption, fluorescence and surface-enhanced Raman scattering (SERS) spectroscopy. The results revealed that the surface attachment through versatile binding sites of S10, N3, N9 and N7 atoms in 6MP produced the interparticle coupling and formed aggregates of AuNPs. As a result, the fluorescence emission enhancement was significantly observed upon AuNPs self-assembly with 6MP. The fluorimetric determination under optimal conditions indicated that 6MP could be quantified in good linearity range of 6.35 x 10(-8) to 3.05 x 10(-7)M, with a low detection limit of 4.82 x 10(-10)M. The relative standard deviation (n=11) was 1.8% at 2.54 x 10(-8)M 6MP concentration level. The proposed method was successfully applied for the determination of 6MP in spiked human urine. The probable fluorescence enhancement mechanism was also discussed there.