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  • Author or Editor: Xia Liu x
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Abstract  

The importance of angiogenesis in tumor growth and metastasis has led to develop new imaging tracers to understand angiogenic vasculature. Based on the previous study, we further focused on the tumor molecular imaging application of the novel peptide Arginine-Arginine-Leucine (Tyr-Cys-Gly-Gly-Arg-Arg-Leu-Gly-Gly-Cys, tRRL) in this study. The cytotoxicity of raioiodinated tRRL (131I-tRRL) in HepG2 cells was assessed by tested cell viability using kit. tRRL was conjugated with fluorescein FITC to observe its binding with tumor cells and human aortic endothelial cells (HAEC) in vitro. Whole body SPECT imaging of varied tumors xenograftes was performed after intravenous injection of 131I-tRRL for 24 h in BALB/c nude mice. Compared with negative control PBS, small peptide tRRL was of non-cytotoxicity. 131I-tRRL could lead to significant cytotoxicity on HepG2 cells when the radioactivity was greater than 370 kBq. In vitro binding experiment and cellular uptake results revealed that tRRL could adhere to tumor cells besides tumor derived endothelial cells. In vivo SPECT imaging, 131I-tRRL mainly accumulated in various tumor tissues, including melanoma, liver cancer and lung cancer bearing mice. In breast cancer xenografte imaging, the tumor has no significant radionuclide accumulation at 24 h after injected of 131I-tRRL. Radioiodinated tRRL offers a noninvasive nuclear imaging method for functional molecular imaging of tumors, and may be a promising candidate carrier for tumor targeted therapy.

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The aim of this study was to investigate the effects of maternal lead exposure on the learning and memory ability and expression of tau protein phosphorylation (P-tau) and beta amyloid protein (Aβ) in hippocampus of mice offspring. Pb exposure initiated from beginning of gestation to weaning. Pb acetate administered in drinking solutions was dissolved in distilled deionized water at the concentrations of 0.1%, 0.5% and 1% groups. On the 21 th of postnatal day, the learning and memory ability of the mouse pups was tested by Water Maze test and the Pb levels in blood and hippocampus of the offspring were also determined. The expression of P-tau and Aβ in hippocampus was measured by immunohistochemistry and Western blotting. The Pb levels in blood and hippocampus of all exposure groups were significantly higher than that of the control group ( P < 0.05). In Water Maze test, the performances of 0.5% and 1% groups were worse than that of the control group ( P < 0.05). The expression of P-tau and Aβ was increased in Pb exposed groups than that of the control group ( P < 0.05). Tau hyper-phosphorylation and Aβ increase in the hippocampus of pups may contribute to the impairment of learning and memory associated with maternal Pb exposure.

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A validated high-performance liquid chromatography (HPLC) method has been developed to analyze the (±)-gossypol in the selection of strains of Candida tropicalis culture. Since gossypol was easily degraded and oxidized, the addition of antioxidant NADPH-Na4 and acetone extraction was chosen to prevent gossypol degradation and gradient elution assay was applied to obtain gossypol resolution. Concentrations of gossypol in C. tropicalis ZD-3 culture 20 μg/mL were determined, and concentration–time profiles were observed. Linearity of the gossypol standard curve by HPLC area method was ranged from 0.1 to 20 μg/mL with Y = 26.954 × X − 29.547, R 2 = 0.9991, and n = 3, with limit of detection (LOD) of 50 ng/mL and lower limit of quantification (LLOQ) of 500 ng/mL. The recovery rate is dose-dependent and ranged from 85.3% to 103.5%. It is a rapid and reliable HPLC method for gossypol quantization in microorganism culture which could be applied in solid fermentation in the feed industry.

Open access

As one of the world’s earliest domesticated crops, barley is a model species for the study of evolution and domestication. Domestication is an evolutionary process whereby a population adapts, through selection; to new environments created by human cultivation. We describe the genome-scanning of molecular diversity to assess the evolution of barley in the Tibetan Plateau. We used 667 Diversity Arrays Technology (DArT) markers to genotype 185 barley landraces and wild barley accessions from the Tibetan Plateau. Genetic diversity in wild barley was greater than in landraces at both genome and chromosome levels, except for chromosome 3H. Landraces and wild barley accessions were clearly differentiated genetically, but a limited degree of introgression was still evident. Significant differences in diversity between barley subspecies at the chromosome level were observed for genes known to be related to physiological and phenotypical traits, disease resistance, abiotic stress tolerance, malting quality and agronomic traits. Selection on the genome of six-rowed naked barley has shown clear multiple targets related to both its specific end-use and the extreme environment in Tibet. Our data provide a platform to identify the genes and genetic mechanisms that underlie phenotypic changes, and provide lists of candidate domestication genes for modified breeding strategies.

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Acta Chromatographica
Authors: Mei-Xia Zhu, Sheng-Nan Li, Hai-Dan You, Bin Han, Zhi-Ping Wang, Yan-Xi Hu, Jin Li and Yu-Feng Liu

High-performance liquid chromatography coupled with photodiode array detection and evaporative light scattering detection (HPLC—DAD—ELSD) was established to determine paeoniflorin and albiflorin simultaneously in Radix Paeoniae Rubra. The assay was performed on a Diamonsil C18 (4.6 mm × 250 mm, 5 μm) column by a gradient elution program with acetonitrile and aqueous formic acid (0.05% v/v) as mobile phase at a flow rate of 1.0 mL min−1. The detection wavelength of DAD was 230 nm, and the evaporator tube temperature of ELSD was set at 110 °C with the nebulizing gas flow rate of 3 L min−1. The temperature of column was kept at 30 °C. The linear ranges of paeoniflorin and albiflorin were within 0.050–1.510 mg mL−1 and 1.007–5.035 mg mL−1. The recoveries of paeoniflorin and albiflorin were 96.2–102.9% and 95.0–102.4%, respectively, while the relative standard deviation (RSD) of them was 0.2–2.5%. This method was quick, simple, accurate, and specific. It could be used for the quality control of Radix Paeoniae Rubra. The proposed approach was expected as a powerful tool for the quality control of Radix Paeoniae Rubra.

Open access

Exploring antibiotic resistant mechanism by microcalorimetry II

Determination of thermokinetic parameters of imipenem hydrolysis with metallo-β-lactamase ImiS

Journal of Thermal Analysis and Calorimetry
Authors: Xia Yang, Lei Feng, Kang-Zhen Xu, Hui-Zhou Gao, Chao Jia, Cheng-Cheng Liu, Jian-Min Xiao, Le Zhai, Li-Sheng Zhou and Ke-Wu Yang

Abstract

In an effort to understand the reaction of antibiotic hydrolysis with B2 metallo-β-lactamases (MβLs), the thermodynamic parameters of imipenem hydrolysis catalyzed by metallo-β-lactamase ImiS from Aeromonas veronii bv. sobria were determined by microcalorimetric method. The values of activation free energy are 86.400 ± 0.043, 87.543 ± 0.034, 88.772 ± 0.024, and 89.845 ± 0.035 kJ mol−1 at 293.15, 298.15, 303.15, and 308.15 K, respectively, activation enthalpy is 18.586 ± 0.009 kJ mol−1, activation entropy is −231.34 ± 0.12 J mol−1 K−1, apparent activation energy E is 21.084 kJ mol−1, and the reaction order is 1.5. The thermodynamic parameters reveal that the imipenem hydrolysis catalyzed by metallo-β-lactammase ImiS is an exothermic and spontaneous reaction.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: Jiaoyun Xia, Yongxian Wang, Junfeng Yu, Shiqiang Li, Lin Tang, Mingqiang Zheng, Xiuqing Liu, Gucai Li, Dengfeng Cheng, Sheng Liang and Duanzhi Yin

Abstract  

Radiolabeling of biologically active molecules with fac-[188Re(CO)3(H2O)3]+ unit has been of primary interest in recent years. Therefore, we herein report ligands L1−L4 (L1=histidine, L2=nitrilotriacetic acid, L3=2-picolylamine-N,N-diacetic acid, L4=bis(2-pyridymethy)amine) that have been evaluated by radiochemical reactions with fac-[188Re(CO)3(H2O)3]+. These reactions yielded the radioactive complexes of fac-[188Re(CO)3L] (L = L1−L4, 188Re tricarbonyl complexes 1–4), which were identified by HPLC. Complexes 1–4, with log P o/w values ranging from −2.23 to 2.18, were obtained with yields of ≥95% using ligand concentrations within 10−6–10−4M range. Thus, specific activities of 220 GBq/μmol could be achieved. Challenge studies with cysteine and histidine revealed high stability for all of these radioactive complexes, and biodistribution studies in mice indicated a fast rate of blood clearance and high rate of total radioactivity excretion occurring primarily through the renal-urinary pathway. In summary, the ligands L1–L4 are potent chelators for the future functionalization of biomolecules labeling with fac-[188Re(CO)3(H2O)3]+.

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