Dyadobacter diqingensis sp. nov., isolated from Baima snow mountain of Diqing Tibetan Autonomous Prefecture in Yunnan province, south-west China.

A Gram-negative, aerobic, nonmotile, rod-shaped and yellow-pigment-producing bacteria was isolated from Baima snow mountain of Diqing Tibetan Autonomous Prefecture in Yunnan province, south-west China and characterized using a polyphasic approach. The results of 16S rRNA gene sequence similarity analysis showed that strain YIM B04101T was closely related to the type strain of Dyadobacter koreensis DSM 19938T (97.81%) and Dyadobacter frigoris AR-3-8T (97.95%). The predominant respiratory quinone was menaquinone-7 (MK-7). The major polar lipid was phosphatidylethanolamine. The major fatty acids were summed feature 3 (C16:1ω7c/C16:1ω6c), C18:1ω9c and C16:0. The DNA G + C content was 43.5 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the strain YIM B04101T belonged to a cluster comprising species of the genus Dyadobacter. However, it differed from its closest relative, Dyadobacter koreensis KCTC 12537T and Dyadobacter frigoris AR-3-8T, in many physiological properties. Based on these phenotypic characteristics and phylogenetic distinctiveness, strain YIM B04101T is considered to be a novel species of the genus Dyadobacter, for which the name Dyadobacter diqingensis sp. nov. is proposed. The type strain is YIM B04101T (= CGMCC 1.19249T = CCTCC AB 2021270).

[Endogenous Release of Nitrogen and Phosphorus in the Danjiangkou Reservoir].

In situ sediments were collected at different sites of the Danjiangkou Reservoir using a columnar sediment sampler, and the release rate of N and P at the sediment-water interface was determined through static incubation experiments and the diffusion model of interstitial water molecules. The results showed that there was a significant difference in the release rate for N and P from sediments collected at five sampling sites. The release rates of NH4+-N and PO43--P under static incubation conditions were 13.07-24.88 mg·(m2·d)-1 and 3.06-6.02 mg·(m2·d)-1, whereas those estimated by Fick's Fist Law were 2.67-7.25 mg·(m2·d)-1 and 0.04-0.18 mg·(m2·d)-1, respectively. Overall, the release rates of N and P in the tributaries were 1.48 and 1.57 times higher than that in the reservoir, respectively, and they tended to decrease from the north to the south. The R/F values of NH4+-N and PO43--P were 3.43-4.98 and 29.67-72.88, respectively. The highest release rates of N and P were observed in the Guojiashan tributary for both methods. However, it was found that the release rates of N and P estimated by Fick's Fist Law were significantly lower than those obtained by the simulation method, indicating that the static incubation experiment with intact sediments allowed the release rates of N and P to be closer to the actual situation compared to the interstitial water molecule diffusion model.

High photon-to-heat conversion efficiency in the wavelength region of 250-1200 nm based on a thermoelectric Bi2Te3 film structure.

In this work, 4-layered SiO2/Bi2Te3/SiO2/Cu film structures were designed and fabricated and the optical properties investigated in the wavelength region of 250-1200 nm for their promising applications for direct solar-thermal-electric conversion. A typical 4-layered film sample with the structure SiO2 (66.6 nm)/Bi2Te3 (7.0 nm)/SiO2 (67.0 nm)/Cu (>100.0 nm) was deposited on a Si or K9-glass substrate by magnetron sputtering. The experimental results agree well with the simulated ones showing an average optical absorption of 96.5%, except in the shorter wavelength region, 250-500 nm, which demonstrates the superior absorption property of the 4-layered film due to the randomly rough surface of the Cu layer resulting from the higher deposition power. The high reflectance of the film structure in the long wavelength region of 2-20 µm will result in a low thermal emittance, 0.064 at 600 K. The simpler 4-layered structure with the thermoelectric Bi2Te3 used as the absorption layer may provide a straightforward way to obtain solar-thermal-electric conversion more efficiently through future study.

Two-Step Oxidation of Refractory Gold Concentrates with Different Microbial Communities.

Bio-oxidation is an effective technology for treatment of refractory gold concentrates. However, the unsatisfactory oxidation rate and long residence time, which cause a lower cyanide leaching rate and gold recovery, are key factors that restrict the application of traditional bio-oxidation technology. In this study, the oxidation rate of refractory gold concentrates and the adaption of microorganisms were analyzed to evaluate a newly developed two-step pretreatment process, which includes a high temperature chemical oxidation step and a subsequent bio-oxidation step. The oxidation rate and recovery rate of gold were improved significantly after the two-step process. The results showed that the highest oxidation rate of sulfide sulfur could reach to 99.01 % with an extreme thermophile microbial community when the pulp density was 5%. Accordingly, the recovery rate of gold was elevated to 92.51%. Meanwhile, the results revealed that moderate thermophiles performed better than acidophilic mesophiles and extreme thermophiles, whose oxidation rates declined drastically when the pulp density was increased to 10% and 15%. The oxidation rates of sulfide sulfur with moderate thermophiles were 93.94% and 65.73% when the pulp density was increased to 10% and 15%, respectively. All these results indicated that the two-step pretreatment increased the oxidation rate of refractory gold concentrates and is a potential technology to pretreat the refractory sample. Meanwhile, owing to the sensitivity of the microbial community under different pulp density levels, the optimization of microbial community in bio-oxidation is necessary in industry.

[Genetic Diversity and Cluster Analysis of Astragalus membranaceus in Gansu Province].

Objective: To investigate the genetic status of Astragalus membranaceuse resources in Gansu province. Methods: Using SSR molecular marker technology for collection of Astragalus membranaceuse resources for genetic diversity analysis and clustering analysis. Results: Nine SSR primers were used on PCR amplification of 57 samples in six main areas of Gansu province,PCR products molecular weighted between 100 ~ 500 bp,the polymorphic loci was 82,the polymorphism rate was 97. 56%,and the average polymorphism information content was 0. 438. At the species level,the number of alleles was 1. 976,the effective number of alleles was 1. 459,Nei' s genetic diversity was 0. 279,Shannon information index was 0. 431,the group of genetic diversity degree was 0. 248,the genetic differentiation among of population was 0. 117,the gene flow coefficient was 3. 775,and the genetic identity was 0. 896 ~ 0. 977. Conclusion: Astragalus membranaceuse resources of Gansu are relatively pure,and have abundant genetic diversity. The genetic variation mainly comes from the group of inside,the genes communication between populations is frequent,and the kinship between population is consistent with their geographic distance. In addition,the results of cluster analysis showed that the Core SSR primers can distinguish Astragalus and Hedysarum in the similarity of 0. 46,but Astragalus membranaceus var. mongholicus,Astragalus membranaceus and Astragalus tongolensis can't be distinguished.

[Astragali Radix and Hedysari Radix molecular identification of SSR primers screening and fingerprints code].

Leguminous related SSR primers were collected, core primers used for Astragali Radix and Hedysari Radix identification were screened and validated by using molecular marker techniques. 6 core primers were selected from 101 pairs of primers, the molecular weight of PCR products was 100-500 bp, which formed 7-12 electrophoresis bands with 55 amplified loci. The percentage of polymorphic loci was 100%, and the average polymorphism information content was 0.371. According to the results of cluster analysis, obtained core primer could completely distinguish 62 mixture samples of Astragali Radix and Hedysari Radix in similarity coefficient of 0.46. Core primers and the corresponding characteristics from gel electrophoresis were tagged. The results provide identification basis for Astragali Radix and Hedysari Radix.

[A surgery protocol to construct zebrafish heart damage and regeneration model].

In recent years, zebrafish has been found to be strikingly capable of heart regeneration at adult stage, which sheds lights on cardiac regenerative medicine, and has also become an important direction for the study of vertebrate genetic and developmental mechanisms. Dissecting the regeneration process and unraveling the underlying molecular and cellular mechanisms might help recover the regeneration capacity of the mammalian heart and further provide instructions to potential therapies for certain cardiac diseases such as myocardial infarction. Here, we introduced a simple surgical method to construct heart injury and regeneration model in zebrafish through amputation of ~20% ventricle. The main procedure includes anaesthetization of adult zebrafish, exposure of the heart by dissecting the nearby abdominal skin and opening the pericardium, and amputation of certain fraction of the ventricle at the cardiac apex under a stereo microscope. Over 90% success rate and easy handling with high reproducibility enable this method to be the most commonly used one for the study of zebrafish heart regeneration.

[Detection of dynamic expression of microRNAs in vivo using a dual-fluorescence reporter system/miRNA Tracer in zebrafish].

microRNAs (miRNAs) are short noncoding RNAs that have been found in a wide variety of organisms and many have been shown to play essential roles by regulating the stability and translation of target messenger RNAs (mRNAs) in animals and plants. Temporal and spatial expression is critical for the regulatory function of miRNAs. To analyze the dynamic expression of particular miRNA in vivo, we constructed a dual-fluorescence reporter system based on Tol2 transposon, in which two reporter genes, enhanced green fluorescent protein (eGFP) and monomeric red fluorescent protein 1 (mRFP1), were driven by the heat shock promoter (hsp) from zebrafish hsp70 gene in an opposite orientation. To sense the existence of a particular miRNA, the complementary DNA sequence of the corresponding miRNA was inserted into the 3'-UTR region of one of the two reporter genes. By injecting the corresponding plasmid DNA into zebrafish embryos, we were able to monitor the abundance and dynamics of miRNA miR-206 in live embryos. To further evaluate this method, we made a collection of transgenic zebrafish with stable integration of dual-fluorescence reporter plasmids targeting different miRNAs, including miR-206 and miR-219. Our results showed that this dual-fluorescence reporter system, which is also called miRNA Tracer, could faithfully monitor the appearance and disappearance of target miRNAs in defined cell lineages during zebrafish development in these fish lines. Our dual-fluorescence reporter/Tracer system provides an important tool for further in-depth studies on miRNAs in zebrafish.