Bacterial Diversity in Linglong Gold Mine, China

<p>Bacteria have been actively regulating cycles of various elements in the environment. To explore the potential bacterial role in gold biogeochemical cycling, this study analyzed the bacterial diversity of mine rock (MR) and surface soil (SS) samples from Linglong gold mine using 16S rRNA gene clone library analysis and cultivation method. From MR, 24 operational taxonomic units (OTUs) were identified from MR, covering 3 phyla and 18 genera. Meanwhile, 24 OTUs were identified from SS, including 4 phyla and 18 genera. Compared with 16S rRNA gene clone library analysis, 28 aerobic and 34 anaerobic isolates were obtained, whereas 26 aerobic and 71 anaerobic strains were isolated from SS. The cultivable bacteria were affiliated with Firmicutes, Proteobacteria and Actinobacteria phyla, and dominated by Firmicutes. These results underscore the high level of bacterial diversity in the gold mine. Our study provides information on the microbial diversity in Linglong gold mine and sheds light on the existence and potential function of bacteria in the gold biogeochemical cycling.</p

Self-Healing and Wide Temperature-Tolerant Cellulose-Based Eutectogels for Reversible Humidity Detection

A kind of ionic conductive gel (also named eutectogel) is developed from an inorganic salt (ZnCl2)-based deep eutectic solvent (DES). The ternary DES consists of ZnCl2, acrylic acid, and water, and cotton linter cellulose is introduced into the DES system to tailor its mechanical and conductive properties. Enabled by the extensive hydrogen bonds and ion–dipole interactions, the obtained eutectogel displays superior ionic conductivity (0.33 S/m), high stretchability (up to 2050%), large tensile strength (1.82 MPa), and wide temperature tolerance (−40 to 60 °C). In particular, the water-induced coordination interactions can tune the strength of hydrogen/ionic bonds in the eutectogels, imparting them with appealing humidity sensing ability in complex and extreme conditions

Ultrasensitive Photoelectrochemical Biosensor Based on DNA Tetrahedron as Nanocarrier for Efficient Immobilization of CdTe QDs-Methylene Blue as Signal Probe with Near-Zero Background Noise

Usually, photoelectrochemical (PEC) assays were devoted to the direct modification of photoactive materials on sensing interface, thereby producing high initial signal and unneglected background noise, which could further result in low sensitivity and restricted detection limit during the detection of targets. In this work, a PEC biosensor with near-zero background noise was established for ultrasensitive microRNA-141 (miRNA-141) detection based on DNA tetrahedron (TET) as nanocarrier for efficient immobilization of CdTe quantum dots (QDs)-Methylene Blue (MB) (TET-QDs-MB complex) as signal probe. First, CdTe QDs as PEC signal indicator was bound to the TET through DNA hybridizations. Then, massive MB as PEC signal enhancer was attached to DNA duplex of the TET immobilized with CdTe QDs via intercalation. Thereafter, the as-prepared TET-QDs-MB complex was considered as an efficient PEC signal probe owing to its excellent photovoltaic properties, thereby avoiding direct modification of photoactive materials on sensing interface and producing a near-zero background noise to improve the sensitivity of this PEC biosensor. Besides, the detection sensitivity could be further improved with the help of the duplex specific nuclease (DSN) enzyme-assisted target cycling amplification strategy. The proposed PEC biosensor performs a wide linear range from 50 aM to 50 pM with a low detection limit of 17 aM for miRNA-141, paving a new and promising horizon for highly accurate and ultrasensitive monitoring of multifarious analytes such as proteins, DNAs, and miRNAs in bioanalysis and disease diagnosis

Evidences of ultraviolet visible spectra of hydrogen sulfide scavenging trans-crotonaldehyde induced by hydrogen peroxide through mitochondria of rat heart

<p>Evidences of ultraviolet visible spectra of hydrogen sulfide scavenging trans-crotonaldehyde (TCA) induced by hydrogen peroxide through mitochondria were probed for the first time. TCA was induced by hydrogen peroxide through mitochondria. When sodium hydrosulfide as hydrogen sulfide donor, comparison with control, ultraviolet visible spectra of TCA decrease were clear. Hydrogen sulfide released by garlic was detected by ultraviolet visible spectroscopy. When garlic as hydrogen sulfide donors, the ultraviolet visible spectra of TCA decrease were very obvious. The findings are strongly recommended that garlic as safe, stable, and controllable hydrogen sulfide donor become a promising drug which is worthy of further study.</p

Molecular Self-Assembly in Conductive Covalent Networks for Selective Nitrate Electroreduction to Ammonia

Electrochemical nitrate (NO3–) reduction in aqueous media provides a useful approach for ammonia (NH3) synthesis. While efforts are focused on developing catalysts, the local microenvironment surrounding the catalyst centers is of great importance for controlling electrocatalytic performance. Here, we demonstrate that a self-assembled molecular iron catalyst integrated in a free-standing conductive hydrogel is capable of selective production of NH3 from NO3– at efficiencies approaching unity. With the electrocatalytic hydrogel, the NH3 selectivity is consistently high under a range of negative biases, which results from the hydrophobicity increase of the polycarbazole-based electrode substrate. In mildly acidic media, proton reduction is suppressed by electro-dewetting of the hydrogel electrode, enhancing the selectivity of NO3– reduction. The electrocatalytic hydrogel is capable of continuous production of NH3 for at least 100 h with NH3 selectivity of ∼89 to 98% at high current densities. Our results highlight the role of constructing an internal hydrophobic surface for electrocatalysts in controlling selectivity in aqueous media

Folate-PEG Conjugates of a Far-Red Light-Activatable Paclitaxel Prodrug to Improve Selectivity toward Folate Receptor-Positive Cancer Cells

We recently demonstrated the far-red light-activatable prodrug of paclitaxel (PTX), Pc-(L-PTX)₂. Upon illumination with a 690 nm laser, Pc-(L-PTX)₂ showed combinational cell killing from rapid photodynamic therapy damage by singlet oxygen, followed by sustained chemotherapy effects from locally released PTX. However, its high lipophilicity (log <i>D</i>_7.4 > 3.1) caused aggregation in aqueous solutions and has nonselectivity toward cancer cells. To solve these important problems, we prepared folic acid (FA)-conjugated and photoactivatable prodrugs of PTX with a polyethylene glycol (PEG) spacer of various chain lengths: FA-PEG_<i>n</i>-Pc-L-PTX [<i>n</i> = 0 (0k, <b>5</b>), ∼23 (1k, <b>7a</b>), ∼45 (2k, <b>7b</b>), ∼80 (3.5k, <b>7c</b>), or ∼114 (5k, <b>7d</b>)]. The PEGylated prodrugs <b>7a–d</b> had a much improved hydrophilicity compared with the non-PEGylated prodrug, Pc-(L-PTX)₂. As the PEG length increased, the hydrophilicity of the prodrug increased (log <i>D</i>_7.4 values: 1.28, 0.09, −0.24, and −0.59 for 1k, 2k, 3.5k, and 5k PEG prodrugs, respectively). Fluorescence spectral data suggested that the PEGylated prodrugs had good solubility in the culture medium at lower concentrations (<1–2 μM), but showed fluorescence quenching due to limited solubility at higher concentrations (>2 μM). Dynamic light scattering indicated that all of the prodrugs formed nanosized particles in both phosphate-buffered saline and culture medium at a concentration of 5 μM. The PEG length affected both nonspecific and folate receptor (FR)-mediated uptake of the prodrugs. The enhanced cellular uptake was observed for the prodrugs with medium-sized PEGs (1k, 2k, or 3.5k) in FR-positive SKOV-3 cells, but not for the prodrugs with no PEG or with the longest PEG (5k), which suggests the optimal range of PEG length around 1k–3.5k for effective uptake of our prodrug system. Consistent with the cellular uptake pattern, medium-sized PEGylated prodrugs showed more potent phototoxic activity (IC_50s, ∼130 nM) than prodrugs with no PEG or the longest PEG (IC₅₀, ∼400 nM). In conclusion, we have developed far-red light-activatable prodrugs with improved water solubility and FR-targeting properties compared with the nontargeted prodrug

Far-Red Light-Activatable Prodrug of Paclitaxel for the Combined Effects of Photodynamic Therapy and Site-Specific Paclitaxel Chemotherapy

Paclitaxel (PTX) is one of the most useful chemotherapeutic agents approved for several cancers, including ovarian, breast, pancreatic, and nonsmall cell lung cancer. However, it causes systemic side effects when administered parenterally. Photodynamic therapy (PDT) is a new strategy for treating local cancers using light and photosensitizer. Unfortunately, PDT is often followed by recurrence due to incomplete ablation of tumors. To overcome these problems, we prepared the far-red light-activatable prodrug of PTX by conjugating photosensitizer via singlet oxygen-cleavable aminoacrylate linker. Tubulin polymerization enhancement and cytotoxicity of prodrugs were dramatically reduced. However, once illuminated with far-red light, the prodrug effectively killed SKOV-3 ovarian cancer cells through the combined effects of PDT and locally released PTX. Ours is the first PTX prodrug that can be activated by singlet oxygen using tissue penetrable and clinically useful far-red light, which kills the cancer cells through the combined effects of PDT and site-specific PTX chemotherapy

Folate-PEG Conjugates of a Far-Red Light-Activatable Paclitaxel Prodrug to Improve Selectivity toward Folate Receptor-Positive Cancer Cells

We recently demonstrated the far-red light-activatable prodrug of paclitaxel (PTX), Pc-(L-PTX)₂. Upon illumination with a 690 nm laser, Pc-(L-PTX)₂ showed combinational cell killing from rapid photodynamic therapy damage by singlet oxygen, followed by sustained chemotherapy effects from locally released PTX. However, its high lipophilicity (log <i>D</i>_7.4 > 3.1) caused aggregation in aqueous solutions and has nonselectivity toward cancer cells. To solve these important problems, we prepared folic acid (FA)-conjugated and photoactivatable prodrugs of PTX with a polyethylene glycol (PEG) spacer of various chain lengths: FA-PEG_<i>n</i>-Pc-L-PTX [<i>n</i> = 0 (0k, <b>5</b>), ∼23 (1k, <b>7a</b>), ∼45 (2k, <b>7b</b>), ∼80 (3.5k, <b>7c</b>), or ∼114 (5k, <b>7d</b>)]. The PEGylated prodrugs <b>7a–d</b> had a much improved hydrophilicity compared with the non-PEGylated prodrug, Pc-(L-PTX)₂. As the PEG length increased, the hydrophilicity of the prodrug increased (log <i>D</i>_7.4 values: 1.28, 0.09, −0.24, and −0.59 for 1k, 2k, 3.5k, and 5k PEG prodrugs, respectively). Fluorescence spectral data suggested that the PEGylated prodrugs had good solubility in the culture medium at lower concentrations (<1–2 μM), but showed fluorescence quenching due to limited solubility at higher concentrations (>2 μM). Dynamic light scattering indicated that all of the prodrugs formed nanosized particles in both phosphate-buffered saline and culture medium at a concentration of 5 μM. The PEG length affected both nonspecific and folate receptor (FR)-mediated uptake of the prodrugs. The enhanced cellular uptake was observed for the prodrugs with medium-sized PEGs (1k, 2k, or 3.5k) in FR-positive SKOV-3 cells, but not for the prodrugs with no PEG or with the longest PEG (5k), which suggests the optimal range of PEG length around 1k–3.5k for effective uptake of our prodrug system. Consistent with the cellular uptake pattern, medium-sized PEGylated prodrugs showed more potent phototoxic activity (IC_50s, ∼130 nM) than prodrugs with no PEG or the longest PEG (IC₅₀, ∼400 nM). In conclusion, we have developed far-red light-activatable prodrugs with improved water solubility and FR-targeting properties compared with the nontargeted prodrug

Additional file 2: of Molecular survey of Enterocytozoon bieneusi in sheep and goats in China

Nucleotide substitutions among some new genotypes of E. bieneusi from this study versus the reported genotype BEB6 (EU 153584). (DOC 132 kb

Additional file 3: Figure S1. of Molecular survey of Enterocytozoon bieneusi in sheep and goats in China

FIG 1 Phylogenetic relationships of the E. bieneusi genotypes identified in this study and other reported genotypes, as inferred by neighbor-joining analysis of ITS gene sequences based on the distances calculated using the Kimura 2-parameter model. Bootstrap values >50 % from 1000 replicates are shown on the nodes. The tree was rooted with GenBank sequence AF059610 from a dog. Known genotypes observed in goats and sheep are marked with open squares and triangles, and the new genotypes in goats and sheep from this study are indicated by filled squares and triangles. (TIF 2078 kb