Host‐induced gene silencing of an important pathogenicity factor PsCPK1 in Puccinia striiformis f. sp. tritici enhances resistance of wheat to stripe rust

Rust fungi are devastating plant pathogens and cause a large economic impact on wheat production worldwide. To overcome this rapid loss of resistance in varieties, we generated stable transgenic wheat plants expressing short interfering RNAs (siRNAs) targeting potentially vital genes of Puccinia striiformis f. sp. tritici (Pst). Protein kinase A (PKA) has been proved to play important roles in regulating the virulence of phytopathogenic fungi. PsCPK1, a PKA catalytic subunit gene from Pst, is highly induced at the early infection stage of Pst. The instantaneous silencing of PsCPK1 by barley stripe mosaic virus (BSMV)‐mediated host‐induced gene silencing (HIGS) results in a significant reduction in the length of infection hyphae and disease phenotype. These results indicate that PsCPK1 is an important pathogenicity factor by regulating Pst growth and development. Two transgenic lines expressing the RNA interference (RNAi) construct in a normally susceptible wheat cultivar displayed high levels of stable and consistent resistance to Pst throughout the T₃ to T₄ generations. The presence of the interfering RNAs in transgenic wheat plants was confirmed by northern blotting, and these RNAs were found to efficiently down‐regulate PsCPK1 expression in wheat. This study addresses important aspects for the development of fungal‐derived resistance through the expression of silencing constructs in host plants as a powerful strategy to control cereal rust diseases.     

Quantum algorithm for programmed cell death of Caenorhabditis elegans

During the development of Caenorhabditis elegans, through cell divisions, a total of exactly 1090 cells are generated, 131 of which undergo programmed cell death (PCD) to result in an adult organism comprising 959 cells. Of those 131, exactly 113 undergo PCD during embryogenesis, subdivided across the cell lineages in the following fashion: 98 for AB lineage; 14 for MS lineage; and 1 for C lineage. Is there a law underlying these numbers, and if there is, what could it be? Here we wish to show that the count of the cells undergoing PCD complies with the cipher laws related to the algorithms of Shor and of Grover.     

夏闲期轮耕对小麦田土壤水分及产量的影响

2007-2010年在宁南旱区研究了夏闲期免耕/深松/免耕(T1)、深松/免耕/深松(T2)、连年翻耕(CT)3种耕作方式对麦田土壤水分及产量的影响.结果表明:经过3年夏闲期T1和T2处理后,农田土壤蓄水效率平均分别较连年翻耕处理提高15.2％和26.5％;T1和T2处理的降水潜在利用率较高,分别达到37.8％和38.5％,降水生产效率平均分别较连年翻耕处理提高9.9％和10.7％.夏闲期轮耕能显著降低休闲期的土壤无效蒸发,有效保蓄小麦生长期的土壤水分.在冬小麦生长前期,T1和T2处理0～200 cm土层土壤水分平均分别较连年翻耕处理增加6.8％和9.4％;在拔节-抽穗-灌浆期,与连年翻耕处理相比,两处理可显著提高0 ～ 200 cm土层土壤蓄水量,对作物产量的贡献率较高.不同轮耕模式在增加作物耗水量的同时也提高了作物产量及水分利用效率,与CT处理相比,3年T1和T2处理作物耗水量平均分别提高5.2％和6.1％,产量分别增加9.9％和10.6％,作物水分生产效率分别提高4.5％和4.3％.相关分析表明,在干旱缺水的宁南地区,冬小麦播种期、拔节-抽穗-灌浆期的土壤蓄水量可显著影响产量,尤其抽穗期的土壤蓄水量对产量的影响更大.     

cGMP regulates hydrogen peroxide accumulation in calcium-dependent salt resistance pathway in <Emphasis Type="Italic">Arabidopsis thaliana</Emphasis> roots

3′,5′-cyclic guanosine monophosphate (cGMP) is an important second messenger in plants. In the present study, roles of cGMP in salt resistance in Arabidopsis roots were investigated. Arabidopsis roots were sensitive to 100 mM NaCl treatment, displaying a great increase in electrolyte leakage and Na⁺/K⁺ ratio and a decrease in gene expression of the plasma membrane (PM) H⁺-ATPase. However, application of exogenous 8Br-cGMP (an analog of cGMP), H₂O₂ or CaCl₂ alleviated the NaCl-induced injury by maintaining a lower Na⁺/K⁺ ratio and increasing the PM H⁺-ATPase gene expression. In addition, the inhibition of root elongation and seed germination under salt stress was removed by 8Br-cGMP. Further study indicated that 8Br-cGMP-induced higher NADPH levels for PM NADPH oxidase to generate H₂O₂ by regulating glucose-6-phosphate dehydrogenase (G6PDH) activity. The effect of 8Br-cGMP and H₂O₂ on ionic homeostasis was abolished when Ca²⁺ was eliminated by glycol-bis-(2-amino ethyl ether)-N,N,N′,N′-tetraacetic acid (EGTA, a Ca²⁺ chelator) in Arabidopsis roots under salt stress. Taken together, cGMP could regulate H₂O₂ accumulation in salt stress, and Ca²⁺ was necessary in the cGMP-mediated signaling pathway. H₂O₂, as the downstream component of cGMP signaling pathway, stimulated PM H⁺-ATPase gene expression. Thus, ion homeostasis was modulated for salt tolerance.     

Production of recombinant human lysozyme in the milk of transgenic pigs

In the swine industry pathogenic infections have a significant negative impact on neonatal survival. Piglets fed with human lysozyme, a natural antibiotic, might be more resistant to gastrointestinal infections. Here we describe the generation of transgenic swine expressing recombinant human lysozyme by somatic cell nuclear transfer. Three cloned female pigs were born, one of which expressed rhLZ at 0.32 ± 0.01 μg/ml in milk, 50-fold higher than that of the pig native lysozyme. Both the transgenic gilts and their progeny appear healthy. Introducing human lysozyme into pigs’ milk has a potential to benefit the piglets by enhancing immune function and defending against pathogenic bacteria, thereby increasing the new born survival rate. This advance could be of great value to commercial swine producers.     

云南三种特色柑橘属果皮精油成分及活性研究

为探究云南特色柑橘属西双版纳曼赛龙柚、元江绿皮冰糖橙、德宏青柠的果皮精油成分及抗肿瘤活性。该研究采用水蒸气蒸馏法提取西双版纳曼赛龙柚、元江绿皮冰糖橙、德宏青柠果皮的精油,通过GC-MS开展定性定量成分分析,并通过MTT法开展果皮精油抑制肿瘤增殖研究。结果表明:德宏青柠果皮精油提取率最高、元江绿皮冰糖橙果皮精油次之、西双版纳曼赛龙柚果皮精油最低; 从西双版纳曼赛龙柚、元江绿皮冰糖橙、德宏青柠的果皮精油中分别鉴定出24种、11种、13种成分,月桂烯、萜品烯是三种精油的共有成分。西双版纳曼赛龙柚和元江绿皮冰糖橙的果皮精油中都含有β-蒎烯、3,7-二甲基-1,6辛二烯-3-醇、柠檬烯、α-松油醇,以及重要香料成分乙酸二甲基苄基原酯和二氢茉莉酮酸甲酯,其中西双版纳曼赛龙柚精油中柠檬烯含量高达72.097%,德宏青柠精油中含有活性成分柠檬醛。三种精油对胃癌细胞MKN-45、人乳腺癌细胞MCF-7和结直肠癌细胞HCT-116均有一定的抗肿瘤活性,并呈剂量依赖关系。该研究结果可为云南三种特色柑橘属植物的开发和应用提供科学依据。     

Loss of the SV2-like Protein SVOP Produces No Apparent Deficits in Laboratory Mice

Neurons express two families of transporter-like proteins − Synaptic Vesicle protein 2 (SV2A, B, and C) and SV2-related proteins (SVOP and SVOPL). Both families share structural similarity with the Major Facilitator (MF) family of transporters. SV2 is present in all neurons and endocrine cells, consistent with it playing a key role in regulated exocytosis. Like SV2, SVOP is expressed in all brain regions, with highest levels in cerebellum, hindbrain and pineal gland. Furthermore, SVOP is expressed earlier in development than SV2 and is one of the neuronal proteins whose expression declines most during aging. Although SV2 is essential for survival, it is not required for development. Because significant levels of neurotransmission remain in the absence of SV2 it has been proposed that SVOP performs a function similar to that of SV2 that mitigates the phenotype of SV2 knockout mice. To test this, we generated SVOP knockout mice and SVOP/SV2A/SV2B triple knockout mice. Mice lacking SVOP are viable, fertile and phenotypically normal. Measures of neurotransmission and behaviors dependent on the cerebellum and pineal gland revealed no measurable phenotype. SVOP/SV2A/SV2B triple knockout mice did not display a phenotype more severe than mice harboring the SV2A/SV2B gene deletions. These findings support the interpretation that SVOP performs a unique, though subtle, function that is not necessary for survival under normal conditions.     

Recent Advances of Natural Polyphenols Activators for Keap1‐Nrf2 Signaling Pathway

The Keap1‐Nrf2/ARE signaling pathway is an important defense system against exogenous and endogenous oxidative stress injury. The dysregulation of the signaling pathway is associated with many diseases, such as cancer, diabetes, and respiratory diseases. Over the years, a wide range of natural products has provided sufficient resources for the discovery of potential therapeutic drugs. Among them, polyphenols possess Nrf2 activation, not only inhibit the production of ROS, inhibit Keap1‐Nrf2 protein–protein interaction, but also degrade Keap1 and regulate the Nrf2 related pathway. In fact, with the continuous improvement of natural polyphenols separation and purification technology and further studies on the Keap1‐Nrf2 molecular mechanism, more and more natural polyphenols monomer components of Nrf2 activators have been gradually discovered. In this view, we summarize the research status of natural polyphenols that have been found with apparent Nrf2 activation and their action modes. On the whole, this review may guide the design of novel Keap1‐Nrf2 activator.     

MCLPMDA: A novel method for miRNA‐disease association prediction based on matrix completion and label propagation

MiRNAs are a class of small non‐coding RNAs that are involved in the development and progression of various complex diseases. Great efforts have been made to discover potential associations between miRNAs and diseases recently. As experimental methods are in general expensive and time‐consuming, a large number of computational models have been developed to effectively predict reliable disease‐related miRNAs. However, the inherent noise and incompleteness in the existing biological datasets have inevitably limited the prediction accuracy of current computational models. To solve this issue, in this paper, we propose a novel method for miRNA‐disease association prediction based on matrix completion and label propagation. Specifically, our method first reconstructs a new miRNA/disease similarity matrix by matrix completion algorithm based on known experimentally verified miRNA‐disease associations and then utilizes the label propagation algorithm to reliably predict disease‐related miRNAs. As a result, MCLPMDA achieved comparable performance under different evaluation metrics and was capable of discovering greater number of true miRNA‐disease associations. Moreover, case study conducted on Breast Neoplasms further confirmed the prediction reliability of the proposed method. Taken together, the experimental results clearly demonstrated that MCLPMDA can serve as an effective and reliable tool for miRNA‐disease association prediction.     

Identification and characterization of potent and selective inhibitors targeting protein tyrosine phosphatase 1B (PTP1B)

Protein tyrosine phosphatase 1B (PTP1B) plays an important role in the negative regulation of insulin and leptin signaling. The development of small molecular inhibitors targeting PTP1B has been validated as a potential therapeutic strategy for Type 2 diabetes (T2D). In this work, we have identified a series of compounds containing dihydropyridine thione and particular chiral structure as novel PTP1B inhibitors. Among those, compound 4b showed moderate activity with IC₅₀ value of 3.33 μM and meanwhile with good selectivity (>30-fold) against TCPTP. The further MOA study of PTP1B demonstrated that compounds 4b is a substrate-competitive inhibitor. The binding mode analysis suggested that compound 4b simultaneously occupies the active site and the second phosphotyrosine (pTyr) binding site of PTP1B. Furthermore, the cell viability assay of compound 4b showed tolerable cytotoxicity in L02 cells, thus 4b may be prospectively used to further in vivo study.