Model of pattern formation in marsh ecosystems with nonlocal interactions

Journal of Mathematical Biology - Smooth cordgrass Spartina alterniflora is a grass species commonly found in tidal marshes. It is an ecosystem engineer, capable of modifying the structure of its...     

Harvesting and seeding of stochastic populations: analysis and numerical approximation

Journal of Mathematical Biology - We study an ecosystem of interacting species that are influenced by random environmental fluctuations. At any point in time, we can either harvest or seed...     

Elaeocarpus reticulatus fruit extracts reduce viability and induce apoptosis in pancreatic cancer cells in vitro

Molecular Biology Reports - Treatment options for pancreatic cancer (PC) are severely limited due to late diagnosis, early metastasis and the inadequacy of chemotherapy and radiotherapy to combat...     

Highly efficient production of diverse rare ginsenosides using combinatorial biotechnology

The rare ginsenosides are recognized as the functionalized molecules after the oral administration of Panax ginseng and its products. The sources of rare ginsenosides are extremely limited because of low ginsenoside contents in wild plants, hindering their application in functional foods and drugs. We developed an effective combinatorial biotechnology approach including tissue culture, immobilization, and hydrolyzation methods. Rh2 and nine other rare ginsenosides were produced by methyl jasmonate-induced culture of adventitious roots in a 10 L bioreactor associated with enzymatic hydrolysis using six β-glycosidases and their combination with yields ranging from 5.54 to 32.66 mg L⁻¹. The yield of Rh2 was furthermore increased by 7% by using immobilized BglPm and Bgp1 in optimized pH and temperature conditions, with the highest yield reaching 51.17 mg L⁻¹ (17.06% of protopanaxadiol-type ginsenosides mixture). Our combinatorial biotechnology method provides a highly efficient approach to acquiring diverse rare ginsenosides, replacing direct extraction from Panax plants, and can also be used to supplement yeast cell factories.     

VPA1500基因缺失对副溶血弧菌生物学特性和致病性的影响

Ⅵ型分泌系统（T6SS）是细菌的一种毒力因子分泌系统,通过分泌蛋白参与调控细菌的环境适应性和毒力。副溶血弧菌具有两个T6SS系统（T6SS1和T6SS2）。[目的] 前期通过差异蛋白质组学技术筛选到副溶血弧菌T6SS1相关的分泌蛋白,本文选择其中的VPA1500为研究对象,研究其基因缺失对副溶血弧菌的生物学特性及致病性的影响。[方法] 利用同源重组技术构建缺失株ΔVPA1500和互补株CΔVPA1500;分析各菌株生长特性、在体外的细菌竞争能力、运动性、细菌鞭毛相关基因的转录水平及生物被膜形成能力的差异,比较各菌株对细胞毒性、小鼠毒力、动物组织载菌量以及组织病理学变化的影响。[结果] 与野生株相比,VPA1500基因缺失后不影响细菌的生长能力、生物被膜形成能力和群集运动,然而ΔVPA1500的浮泳运动能力显著下降;进一步通过透射电镜观察和实时定量PCR检测发现,VPA1500缺失影响副溶血弧菌鞭毛的形成;细菌竞争实验显示缺失VPA1500基因降低了副溶血弧菌野生株体外对大肠杆菌的杀伤能力;ΔVPA1500对细胞毒性、小鼠毒力以及在动物组织的定殖能力均显著低于野生株,互补株毒力基本恢复至野生株水平;组织病理学结果进一步表明,缺失VPA1500基因能够降低副溶血弧菌对小鼠组织的损伤。[结论] VPA1500参与副溶血弧菌的体外细菌竞争能力、浮游运动能力和致病性。     

DcR3在甲状腺乳头状癌中的表达及临床意义

应用RT-PCR、Westem blot、免疫组化分别检测甲状腺乳头状癌组织与癌旁正常甲状腺组织标本中DcR3mRNA及蛋白的表达情况,探讨DcR3在甲状腺乳头状癌组织中的表达及,临床意义。RT-PCR检测显示,甲状腺乳头状癌中DcR3 mRNA的表达明显高于正常甲状腺组织（P〈0．05）：Western blot提示,DcR3蛋白在甲状腺乳头状癌中表达比正常甲状腺组织高（P〈0．05）;免疫组化显示,DcR3蛋白在甲状腺乳头状癌中高表达（P〈0．05）。DcR3mRNA及蛋白质在甲状腺乳头状癌及正常甲状腺组织间的表达差异有统计学意义（P〈0．05）。DcR3基因及蛋白在甲状腺乳头状癌中高表达,提示DcR3可能促进了甲状腺乳头状癌的发生发展。     

Identification of DNA-binding proteins by incorporating evolutionary information into pseudo amino acid composition via the top-n-gram approach

DNA-binding proteins are crucial for various cellular processes and hence have become an important target for both basic research and drug development. With the avalanche of protein sequences generated in the postgenomic age, it is highly desired to establish an automated method for rapidly and accurately identifying DNA-binding proteins based on their sequence information alone. Owing to the fact that all biological species have developed beginning from a very limited number of ancestral species, it is important to take into account the evolutionary information in developing such a high-throughput tool. In view of this, a new predictor was proposed by incorporating the evolutionary information into the general form of pseudo amino acid composition via the top-n-gram approach. It was observed by comparing the new predictor with the existing methods via both jackknife test and independent data-set test that the new predictor outperformed its counterparts. It is anticipated that the new predictor may become a useful vehicle for identifying DNA-binding proteins. It has not escaped our notice that the novel approach to extract evolutionary information into the formulation of statistical samples can be used to identify many other protein attributes as well.     

Toxicity of Binary Mixtures of Enantiomers in Chiral Organophosphorus Insecticides: The Significance of Joint Effects Between Enantiomers

The existence of enantiomer‐enriched mixtures of chiral pesticides in the environment is overwhelmingly positive. However, interactions between enantiomers have not been considered so far in risk assessments. Here, we chose three organophosphorus pesticides as representative chiral pesticides to investigate the possible interaction mode between each pair of enantiomers both in in vivo and in vitro. Data show that the enantiomers of methamidophos and profenofos have a simple additive effect, <zaq;1> whereas fensulfothion acts as an antagonist in AChE‐inhibition model. In contrast, enantiomers of methamidophos and fensulfothion had an additive effect in an acute toxicity test against Daphnia magna. A synergistic effect was observed in the joint toxicity of the profenofos enantiomers. The ability for enantiospecific biodegradation in the in vivo model contributed to the different interaction observed between the in vitro and in vivo models. Moreover, binding affinities were suspected as another reason for the different mode of action of mixture enantiomers. Our study recommends using a joint research model to treat chiral compounds in the real environment. Chirality 25:787–792, 2013. © 2013 Wiley Periodicals, Inc.     

RhEXPA4, a rose expansin gene, modulates leaf growth and confers drought and salt tolerance to Arabidopsis

Drought and high salinity are major environmental conditions limiting plant growth and development. Expansin is a cell-wall-loosening protein known to disrupt hydrogen bonds between xyloglucan and cellulose microfibrils. The expression of expansin increases in plants under various abiotic stresses, and plays an important role in adaptation to these stresses. We aimed to investigate the role of the RhEXPA4, a rose expansin gene, in response to abiotic stresses through its overexpression analysis in Arabidopsis. In transgenic Arabidopsis harboring the Pro _RhEXPA4 ::GUS construct, RhEXPA4 promoter activity was induced by abscisic acid (ABA), drought and salt, particularly in zones of active growth. Transgenic lines with higher RhEXPA4 level developed compact phenotypes with shorter stems, curly leaves and compact inflorescences, while the lines with relatively lower RhEXPA4 expression showed normal phenotypes, similar to the wild type (WT). The germination percentage of transgenic Arabidopsis seeds was higher than that of WT seeds under salt stress and ABA treatments. Transgenic plants showed enhanced tolerance to drought and salt stresses: they displayed higher survival rates after drought, and exhibited more lateral roots and higher content of leaf chlorophyll a under salt stress. Moreover, high-level RhEXPA4 overexpressors have multiple modifications in leaf blade epidermal structure, such as smaller, compact cells, fewer stomata and midvein vascular patterning in leaves, which provides them with more tolerance to abiotic stresses compared to mild overexpressors and the WT. Collectively, our results suggest that RhEXPA4, a cell-wall-loosening protein, confers tolerance to abiotic stresses through modifying cell expansion and plant development in Arabidopsis.