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951.
952.
An endophytic bacteriumn identified as Acinetobacter johnsonii strain 3–1 was isolated from surface-sterilized roots of Beta vulgaris. Its effect on sugar beet seedling growth was studied using pot assays and field experiments. This strain promoted beet seedling
growth following seed inoculation by seed dipping. Plant height and dry weight of beet increased by 19% and 69%, respectively,
compared with controls. Strain 3–1 exhibited the ability to increase absorption of N, P, K, and Mg elements from soil and
increase the content of vitamins B and C, and protein within beet. In addition, the strain also produced a phytohormone-auxin,
produced nearly twice as much IAA as that produced by strain 2–2, and was able to solubilize phosphates. The concentration of dissolved P in the medium was 180.5 mg L−1 after 4 days of incubation. In field experiments, strain 3–1 significantly increased the content of sucrose, fructose, and
the yield of the beet. The growth-promoting properties of Acinetobacter johnsonii strain 3–1 indicates that this promising isolate merits further investigation into its symbiosis with beet plants and its
potential application in agriculture. 相似文献
953.
Linlin Zhang Jiankui Zhou Jinxiong Han Bian Hu Ningning Hou Yun Shi Xingxu Huang Xin Lou 《PloS one》2016,11(4)
The CRISPR/Cas9 system has been developed as an easy-handle and multiplexable approach for engineering eukaryotic genomes by zygote microinjection of Cas9 and sgRNA, while preparing Cas9 for microinjection is laborious and introducing inconsistency into the experiment. Here, we describe a modified strategy for gene targeting through using oocyte-specific Cas9 transgenic mouse. With this mouse line, we successfully achieve precise gene targeting by injection of sgRNAs only into one-cell-stage embryos. Through comprehensive analysis, we also show allele complexity and off-target mutagenesis induced by this strategy is obviously lower than Cas9 mRNA/sgRNA injection. Thus, injection of sgRNAs into oocyte-specific Cas9 transgenic mouse embryo provides a convenient, efficient and reliable approach for mouse genome editing. 相似文献
954.
Using D-pinitol (= 3-O-methyl-D-chiro-inositol) as starting material, a concise synthesis of 4/5-deoxy-4/5-nucleobase derivatives 11-19 has been achieved. The key intermediate 9 was obtained in good yield via an epoxidation from mono-methanesulfonate of D-pinitol. The process of opening of the epoxide ring in 9 by nucleobases appeared to be regioselective in presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). All the synthesized carbocyclic nucleosides were assayed against several viruses and tumors such as HIV-1, HSV-1, and HSV-2, and lung and bladder cancer. However, only compounds 14b, 14a, 16a, 16b, and 19 showed mild inhibitory effect against human lung cancer cell lines (PG) with IC50 values ranging from 50 to 100 microM, and the other compounds did not exhibit any significant antiviral activity or cytotoxicity even at concentrations up to 200 microM. 相似文献
955.
Qiao Cao Yue Wang Feifei Chen Yongjie Xia Jingyu Lou Xue Zhang Nana Yang Xiaoxu Sun Qin Zhang Chao Zhuo Xi Huang Xin Deng Cai-Guang Yang Yan Ye Jing Zhao Min Wu Lefu Lan 《PLoS pathogens》2014,10(8)
The rhl quorum-sensing (QS) system plays critical roles in the pathogenesis of P. aeruginosa. However, the regulatory effects that occur directly upstream of the rhl QS system are poorly understood. Here, we show that deletion of gene encoding for the two-component sensor BfmS leads to the activation of its cognate response regulator BfmR, which in turn directly binds to the promoter and decreases the expression of the rhlR gene that encodes the QS regulator RhlR, causing the inhibition of the rhl QS system. In the absence of bfmS, the Acka-Pta pathway can modulate the regulatory activity of BfmR. In addition, BfmS tunes the expression of 202 genes that comprise 3.6% of the P. aeruginosa genome. We further demonstrate that deletion of bfmS causes substantially reduced virulence in lettuce leaf, reduced cytotoxicity, enhanced invasion, and reduced bacterial survival during acute mouse lung infection. Intriguingly, specific missense mutations, which occur naturally in the bfmS gene in P. aeruginosa cystic fibrosis (CF) isolates such as DK2 strains and RP73 strain, can produce BfmS variants (BfmSL181P, BfmSL181P/E376Q, and BfmSR393H) that no longer repress, but instead activate BfmR. As a result, BfmS variants, but not the wild-type BfmS, inhibit the rhl QS system. This study thus uncovers a previously unexplored signal transduction pathway, BfmS/BfmR/RhlR, for the regulation of rhl QS in P. aeruginosa. We propose that BfmRS TCS may have an important role in the regulation and evolution of P. aeruginosa virulence during chronic infection in CF lungs. 相似文献
956.
Lou H Chen M Black SS Bushell SR Ceccarelli M Mach T Beis K Low AS Bamford VA Booth IR Bayley H Naismith JH 《PloS one》2011,6(10):e25825
Antibiotic-resistant bacteria, particularly gram negative species, present significant health care challenges. The permeation of antibiotics through the outer membrane is largely effected by the porin superfamily, changes in which contribute to antibiotic resistance. A series of antibiotic resistant E. coli isolates were obtained from a patient during serial treatment with various antibiotics. The sequence of OmpC changed at three positions during treatment giving rise to a total of four OmpC variants (denoted OmpC20, OmpC26, OmpC28 and OmpC33, in which OmpC20 was derived from the first clinical isolate). We demonstrate that expression of the OmpC K12 porin in the clinical isolates lowers the MIC, consistent with modified porin function contributing to drug resistance. By a range of assays we have established that the three mutations that occur between OmpC20 and OmpC33 modify transport of both small molecules and antibiotics across the outer membrane. This results in the modulation of resistance to antibiotics, particularly cefotaxime. Small ion unitary conductance measurements of the isolated porins do not show significant differences between isolates. Thus, resistance does not appear to arise from major changes in pore size. Crystal structures of all four OmpC clinical mutants and molecular dynamics simulations also show that the pore size is essentially unchanged. Molecular dynamics simulations suggest that perturbation of the transverse electrostatic field at the constriction zone reduces cefotaxime passage through the pore, consistent with laboratory and clinical data. This subtle modification of the transverse electric field is a very different source of resistance than occlusion of the pore or wholesale destruction of the transverse field and points to a new mechanism by which porins may modulate antibiotic passage through the outer membrane. 相似文献
957.
Masahiro Yao Farida Latif Mary Lou Orcutt Igor Kuzmin Thomas Stackhouse Fang wei Zhou Kalman Tory Fuh mei Duh Frances Richards Eamonn Maher Sal LaForgia Kay Huebner Denis Le Pasilier Marston Linehan Michael Lerman Berton Zbar 《Human genetics》1993,92(6):605-614
Von Hippel-Lindau disease (VHL) is an inherited multisystem neoplastic disorder. We prepared a 2.5-megabase (Mb) restriction map of the region surrounding the VHL gene and identified and characterized overlapping deletions in three unrelated patients affected with VHL. The smallest nested deletion (100 kb) was located within a 510-kb NruI fragment detected by 19–63. The rearrangements detected will be useful in isolating and evaluating candidate cDNAs for the VHL gene. The detailed physical map will be useful in studying the organization and structure of genes in the VHL region. 相似文献
958.
Xiao-Li Ping Bao-Fa Sun Lu Wang Wen Xiao Xin Yang Wen-Jia Wang Samir Adhikari Yue Shi Ying Lv Yu-Sheng Chen Xu Zhao Ang Li Ying Yang Ujwal Dahal Xiao-Min Lou Xi Liu Jun Huang Wei-Ping Yuan Xiao-Fan Zhu Tao Cheng Yong-Liang Zhao Xinquan Wang Jannie M Rendtlew Danielsen Feng Liu Yun-Gui Yang 《Cell research》2014,24(2):177-189
959.
本研究将生产上常用的糖化菌(Asp.niger3.4309)与酒精产生菌(Z.mobilis)共同固定在海藻酸钙凝胶中,以淀粉为原料进行固定化细胞酒精发酵实验,并就pH、温度、通气量。淀粉浓度等对发酵的影响进行了探讨,认为当PH为5.0~5.5,温度为30℃~33℃时乙醇产率最高(Yp/s可达0.39)。而淀粉浓度、通气量对共固定化细胞酒精发酵有显著影响,二者存在着较强的交互作用,在发酵过程中根据淀粉粘度情况调节通气量将有助于提高乙醇产率。 相似文献
960.