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.

Silver-mediated trifluoromethylation-iodination of arynes.

An unprecedented silver-mediated vicinal trifluoromethylation-iodination of arynes that quickly introduces CF(3) and I groups onto aromatic rings in a single step to give o-trifluoromethyl iodoarenes has been developed. A new reactivity of AgCF(3) has been revealed, and 2,2,6,6-tetramethylpiperidine plays an important role in this difunctionalization reaction.

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.

Copper-mediated fluoroalkylation reactions with iododifluoroacetamides: controlling the selectivity among cross-coupling, intramolecular cyclization, and homocoupling reactions.

Cu-mediated fluoroalkylation reactions with iododifluoroacetamides 1 have been systematically investigated. It was found that three types of reactions may coexist in Cu-mediated reactions between iododifluoroacetamides and aryl/alkenyl iodides: cross-coupling, intramolecular cyclization, and homocoupling reactions. The selectivity among these three types of reactions could be controlled by tuning the substituents on the nitrogen atom of iododifluoroacetamides, and/or by removing the cross-coupling reaction partner (aryl/alkenyl halides). The general rule is as follows: (a) in the presence of proper aryl/alkenyl iodides, the cross-coupling products 2 (or 6) are generally formed as the major products; (b) in the absence of aryl/alkenyl iodides, and when R(1) = alkyl and R(2) = aryl groups, or when R(1) = R(2) = aryl groups, the intramolecular cyclization products 3 can be formed predominantly; and (c) in the absence of aryl/alkenyl iodides, and when R(1) = R(2) = alkyl groups, or when R(1) = H and R(2) = alkyl, aryl groups, the homocoupling products 4 can be formed dominantly. Our experimental results also indicate that in many cases when cross-coupling, homocoupling, and intramolecular cyclization reactions coexist in the Cu-mediated reaction system, the reactivity decreases in the following order: cross-coupling > intramolecular cyclization > homocoupling.

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.

C-F bond cleavage by intramolecular S(N)2 reaction of alkyl fluorides with O- and N-nucleophiles.

The nucleophilic substitution of alkyl fluorides was achieved in the intramolecular reactions with O- and N-nucleophiles. The intramolecular defluorinative cyclization reaction was influenced by the nature of nucleophiles, the size of the ring to be formed, and the comformational rigidity of the precursors. Intermolecular nucleophilic substitution reactions of alkyl fluorides under similar reaction conditions were found to be difficult. The stereochemistry study of the current C-F bond cleavage reaction showed a complete configurational inversion, which supports an intramolecular S(N)2 reaction mechanism.

Synthesis of fluorinated beta-ketosulfones and gem-disulfones by nucleophilic fluoroalkylation of esters and sulfinates with di- and monofluoromethyl sulfones.

An efficient and practically useful method for the preparation of alpha-functionalized mono- and difluoro(phenylsulfonyl)methanes by using a nucleophilic fluoroalkylation methodology was developed. Alpha,alpha-difluoro-beta-ketosulfones, alpha-monofluoro-beta-ketosulfones, and alpha-fluoro disulfones were successfully prepared in excellent yields by nucleophilic fluoroalkylation of esters and sulfinates with PhSO(2)CF(2)H and PhSO(2)CH(2)F reagents.

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.

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.

Nucleophilic fluoroalkylation of alpha,beta-enones, arynes, and activated alkynes with fluorinated sulfones: probing the hard/soft nature of fluorinated carbanions.

We have successfully accomplished the nucleophilic fluoroalkylation of alpha,beta-enones, arynes, and activated alkynes with fluorinated sulfones. It was found that for acylic alpha,beta-enones, although the reaction medium and the structure of the enones can all influence the regioselectivity of the nucleophilic alkylation reactions, the hard/soft nature of the carbanions played a major role. By using the 1,4- and 1,2-addition product ratio as a probe to determine the hard/soft nature of the above-mentioned four halogenated carbanions, the order of the softness of these carbanions can be given as follows: [(PhSO2)2CF(-)] (20) approximately = PhSO2CCl2(-) (32) > PhSO2CHF(-) (31) > PhSO2CF2(-) (30). In the case of fluoroalkylation of aryne (35 as the precursor) and alpha,beta-acetylenic ketones 46 with fluorobis(phenylsulfonyl)methane (21), fluorobis(phenylsulfonyl)methylated arenes 36 and beta-fluorobis(phenylsulfonyl)methylated alpha,beta-enones 47 were obtained as the corresponding products in good yields. During the reaction between 2-fluoro-2-(phenylsulfonyl)acetophenone (34) and arynes or activated alkynes 46, an intramolecular tandem reaction process leads to the formation of acyl-fluoroalkylated arenes 43 or alpha-acyl-beta-fluoroalkylated alpha,beta-enones 48. It turned out that the softness of a fluorine-bearing carbanion (such as 20 or 33 derived from 21 or 34) plays a crucial role for the success of the nucleophilic fluoroalkylation reactions with arynes and some activated alkynes (alpha,beta-acetylenic ketones).

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.

[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.

Chlorodifluoromethyl phenyl sulfone: a novel non-ozone-depleting substance-based difluorocarbene reagent for O- and N-difluoromethylations.

Chlorodifluoromethyl phenyl sulfone, a previously unknown compound that can be readily prepared from non-ODS-based precursors, was found to act as a robust difluorocarbene reagent for O- and N-difluoromethylations.

Stereoselective nucleophilic monofluoromethylation of N-(tert-butanesulfinyl)imines with fluoromethyl phenyl sulfone.

[reaction: see text] Highly stereoselective nucleophilic monofluoromethylation of (R)-(tert-butanesulfinyl)imines with fluoromethyl phenyl sulfone was achieved to afford alpha-monofluoromethylamines with a nonchelation-controlled stereoselectivity mode. By using the same chemistry, (R)-(tert-butanesulfinyl)imines bearing a terminal tosylate (OTs) group can be converted to alpha-monofluoromethylated cyclic secondary amines with high stereoselectivity.

Stereoselective [3+2] cycloaddition of N-tert-butanesulfinyl imines to arynes facilitated by a removable PhSO2CF2 group: synthesis and transformation of cyclic sulfoximines.

An unprecedented [3+2] cycloaddition between N-tert-butanesulfinyl imines and arynes provides a stereoselective method for the synthesis of cyclic sulfoximines. Not only does the difluoro(phenylsulfonyl)methyl group play an important role in facilitating the cycloaddition reaction, it can also be removed or substituted through the transformation of the difluorinated cyclic sulfoximines to cyclic sulfinamides.