DNA barcoding of Cymbidium by genome skimming: Call for next-generation nuclear barcodes

Cymbidium is an orchid genus that has undergone rapid radiation and has high ornamental, economic, ecological and cultural importance, but its classification based on morphology is controversial. The plastid genome (plastome), as an extension of plant standard DNA barcodes, has been widely used as a potential molecular marker for identifying recently diverged species or complicated plant groups. In this study, we newly generated 237 plastomes of 50 species (at least two individuals per species) by genome skimming, covering 71.4% of members of the genus Cymbidium. Sequence-based analyses (barcoding gaps and automatic barcode gap discovery) and tree-based analyses (maximum likelihood, Bayesian inference and multirate Poisson tree processes model) were conducted for species identification of Cymbidium. Our work provides a comprehensive DNA barcode reference library for Cymbidium species identification. The results show that compared with standard DNA barcodes (rbcL + matK) as well as the plastid trnH-psbA, the species identification rate of the plastome increased moderately from 58% to 68%. At the same time, we propose an optimized identification strategy for Cymbidium species. The plastome cannot completely resolve the species identification of Cymbidium, the main reasons being incomplete lineage sorting, artificial cultivation, natural hybridization and chloroplast capture. To further explore the potential use of nuclear data in identifying species, the Skmer method was adopted and the identification rate increased to 72%. It appears that nuclear genome data have a vital role in species identification and are expected to be used as next-generation nuclear barcodes.     

Efficient polymer-mediated delivery system for thiocyclam: Nanometerization remarkably improves the bioactivity toward green peach aphids

The unscientific application of synthetic pesticides has brought various negative effects on the environment, hindering the sustainable development of agriculture. Nanoparticles can be applied as carriers to improve pesticide delivery, showing great potential in the development of pesticide formulation in recent years. Herein, a star polymer (SPc) was constructed as an efficient pesticide nanocarrier/adjuvant that could spontaneously assemble with thiocyclam or monosultap into a complex, through hydrophobic association and hydrogen bonding, respectively, with the pesticide-loading contents of 42.54% and 19.3%. This complexation reduced the particle sizes of thiocyclam from 543.54 to 52.74 nm for pure thiocyclam, and 3 814.16 to 1 185.89 nm for commercial preparation (cp) of thiocyclam. Interestingly, the introduction of SPc decreased the contact angles of both pure and cp thiocyclam on plant leaves, and increased the plant uptake of cp thiocyclam to 2.4–1.9 times of that without SPc. Meanwhile, the SPc could promote the bioactivity of pure/cp thiocyclam against green peach aphids through leaf dipping method and root application. For leaf dipping method, the 50% lethal concentration decreased from 0.532 to 0.221 g/L after the complexation of pure thiocyclam with SPc, and that decreased from 0.390 to 0.251 g/L for cp thiocyclam. SPc seems a promising adjuvant for nanometerization of both pure and cp insecticides, which is beneficial for improving the delivery efficiency and utilization rate of pesticides.     

Remifentanil preconditioning alleviating brain damage of cerebral ischemia reperfusion rats by regulating the JNK signal pathway and TNF-α/TNFR1 signal pathway

Tumor necrosis factor (TNF) and the TNF receptor (TNFR) superfamily play very important roles for cell death as well as normal immune regulation. Previous studies have strongly suggested that c-Jun N-terminal kinase (JNK) signaling pathway plays a critical role in ischemic brain injury. The purpose of this investigation was to examine the protective effect of remifentanil preconditioning in cerebral ischemia/reperfusion injury (CIR) and its possible molecular mechanism. Results showed that Remifentanil pretreatment significantly decreased the CD4⁺ and increased the CD8⁺ in cerebral tissues. Additionally, CD4⁺/CD8⁺ in CIR + Remifentanil group was markedly lower than that in CIR group. TNF-α and TNFR1 in CIR + Remifentanil group rats was found to be significant lower than that in CIR group rats. The expression levels of Cyt-c, caspase-3, caspase-9 and pJNK proteins in brain of CIR + Remifentanil group rats were found to significantly decreased compared to CIR group rats. In addition, decreased ROS level indirectly inhibit JNK activation and cell death in CIR rat receiving Remifentanil preconditioning. From current experiment results, at least two signal pathways involve into the process of Remifentanil preconditioning inhibiting cerebral damage induced by ischemia reperfusion. The inhibitory effects of Remifentanil preconditioning on the brain damage are achieved probably through blocking the activation of TNF-α/TNFR1, JNK signal transduction pathways, which implies that Remifentanil preconditioning may be a potential and effective way for prevention of the ischemic/reperfusion injury through the suppression extrinsic apoptotic signal pathway induced by TNF-α/TNFR1, JNK signal pathways. Taken together, this study indicated that regulation of the TNF-α/TNFR1 and JNK signal pathways may provide a new therapy for cerebral damage induced by ischemia and reperfusion.     

Friend or foe: Multiple roles of adipose tissue in cancer formation and progression

Obesity is well-known as the second factor for tumorigenesis after smoking and is bound up with the malignant progression of several kinds of cancers, including esophageal cancer, liver cancer, colorectal cancer, kidney cancer, and ovarian cancer. The increased morbidity and mortality of obesity-related cancer are mostly attributed to dysfunctional adipose tissue. The possible mechanisms connecting dysfunctional adipose tissue to high cancer risk mainly focus on chronic inflammation, obesity-related microenvironment, adipokine secretion disorder, and browning of adipose tissue, and so forth. The stromal vascular cells in adipose tissue trigger chronic inflammation through secreting inflammatory factors and promote cancer cell proliferation. Hypertrophic adipose tissues lead to metabolic disorders of adipocytes, such as abnormal levels of adipokines that mediate cancer progression and metastasis. Cancer patients often show adipose tissue browning and cancerous cachexia in an advanced stage, which lead to unsatisfied chemotherapy effect and poor prognosis. However, increasing evidence has shown that adipose tissue may display quite opposite effects in cancer development. Therefore, the interaction between cancers and adipose tissue exert a vital role in mediates adipose tissue dysfunction and further leads to cancer progression. In conclusion, targeting the dysfunction of adipose tissue provides a promising strategy for cancer prevention and therapy.     

Disabling receptor ensembles with rationally designed interface peptidomimetics

Members of the erbB family receptor tyrosine kinases (erbB1, erbB2, erbB3, and erbB4) are overexpressed in a variety of human cancers and represent important targets for the structure-based drug design. Homo- and heterodimerization (oligomerization) of the erbB receptors are known to be critical events for receptor signaling. To block receptor self-associations, we have designed a series of peptides derived from potential dimerization surfaces in the extracellular subdomain IV of the erbB receptors (erbB peptides). In surface plasmon resonance (BIAcore) studies, the designed peptides have been shown to selectively bind to the erbB receptor ectodomains and isolated subdomain IV of erbB2 with submicromolar affinities and to inhibit heregulin-induced interactions of erbB3 with different erbB receptors. A dose-dependent inhibition of native erbB receptor dimerization by the erbB peptides has been observed in 32D cell lines transfected with different combinations of erbB receptors. The peptides effectively inhibited growth of two types of transformed cells overexpressing different erbB receptors, T6-17 and 32D, in standard MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and cell viability assays. The study identifies distinct loops within the membrane-proximal part of the subdomain IV as potential receptor-receptor interaction sites for the erbB receptors and demonstrates the possibility of disabling receptor activity by structure-based targeting of the dimerization interfaces. Molecular models for possible arrangement of the erbB1.EGF complex, consistent with the involvement of subdomain IV in inter-receptor interactions, are proposed. Small dimerization inhibitors described herein can be useful as probes to elucidate different erbB signaling pathways and may be developed as therapeutic agents.     

基于上转换纳米材料的免疫检测技术应用

免疫分析法具有简便、快速、准确等特点，广泛应用于医学、食品、环境等领域检测，将免疫分析方法与纳米材料相结合可以提高免疫分析的性能。与传统纳米材料相比，上转换纳米颗粒（upconversion nanoparticles，UCNPs）具有光稳定性好、发光寿命长和狭窄及可调整的发射带等优秀的光学性质，与免疫分析相结合可显著降低背景噪声，提高分析灵敏度。本文简要介绍了UCNPs的发光机制，对UCNPs的合成和表面修饰方法进行了总结，并详细论述荧光共振能量转移、内滤效应、磁分离技术、上转化连接免疫吸附技术和上转换免疫层析技术五种基于UCNPs的免疫检测技术，最后对该技术所面临的挑战和前景进行总结和展望，以期为UCNPs免疫检测技术的发展提供理论指导。     

Arginine vasopressin induces periaqueductal gray release of enkephalin and endorphin relating to pain modulation in the rat

Previous study has proven that microinjection of arginine vasopressin (AVP) into periaqueductal gray (PAG) raises the pain threshold, in which the antinociceptive effect of AVP can be reversed by PAG pretreatment with V2 rather than V1 or opiate receptor antagonist. The present work investigated the AVP effect on endogenous opiate peptides, oxytocin (OXT) and classical neurotransmitters in the rat PAG. The results showed that AVP elevated the concentrations of leucine-enkephalin (L-Ek), methionine-enkephalin (M-Ek) and beta-endorphin (beta-Ep), but did not change the concentrations of dynorphinA(1-13) (DynA(1-13)), OXT, classical neurotransmitters including achetylcholine (Ach), choline (Ch), serotonin (5-HT), gamma-aminobutyric acid (GABA), glutamate (Glu), dopamine (DA), norepinephrine (NE) and epinephrine (E), and their metabolic products in PAG perfusion liquid. Pain stimulation increased the concentrations of AVP, L-EK, M-Ek, beta-Ep, 5-HT and 5-HIAA (5-HT metabolic product), but did not influence the concentrations of DynA(1-13), OXT, the other classical neurotransmitters and their metabolic products. PAG pretreatment with naloxone - an opiate receptor antagonist completely attenuated the pain threshold increase induced by PAG administration of AVP, but local pretreatment of OXT or classical neurotransmitter receptor antagonist did not influence the pain threshold increase induced by PAG administration of AVP. The data suggested that AVP in PAG could induce the local release of enkephalin and endorphin rather than dynophin, OXT and classical neurotransmitters to participate in pain modulation.     

杜氏盐藻psaB基因cDNA克隆及系统进化分析

根据真核生物莱茵衣藻(Chlamydomonas reinhardtii)、Chlamydomonas moewusii及Chlorella vulgaris等光系统Ⅰ反应中心蛋白psaB基因的氨基酸高度保守序列,设计一对简并引物,利用TRIzol试剂提取杜氏盐藻(Dunaliella salina)细胞的总RNA,通过RT-PCR,得到的一段长为1.8kb左右的cDNA片段。PCR产物经T-A克隆并测序以及测序结果推导成氨基酸序列进行同源性比较,表明所克隆的1815bp序列为杜氏盐藻光系统Ⅰ反应中心psaB基因的cDNA片段,GenBank收录号为AY820754。根据已经得到的psaB的核苷酸序列推导成氨基酸序列与一些已知物种的psaB氨基酸序列相比较,同源性分别为Chlamydomonas reinhardtii 92%,Chlamydomonas moewusii 91%,Chlorella vulgaris 86%,Mesostigma viride 85%,Phy -scomitrella patenssubsp.Patens 85%,Nephroselmis olivacea 84%。此外,psaB密码子偏爱性分析表明:杜氏盐藻psaB基因第三位密码子A和T的组成分别为35.7%和39.17%,而G和C分别为7.27%和17.85%,即杜氏盐藻psaB基因密码子的组成大多为NNA和NNT。根据psaB基因的特征,作者对绿藻门的50个物种的psaB基因作了进化分析,结果表明:杜氏盐藻与Haematococcaceae中的大多数种类进化地位最为接近,这为更进一步弄清杜氏盐藻的遗传背景提供了理论依据。     

乳腺癌实验动物模型的制备与应用

乳腺癌实验动物模型在研究人类乳腺癌的生物学行为及治疗等方面起着非常重要的作用。根据制备方法及研究目的的不同,乳腺癌实验动物模型可分为自发性、诱发性、移植性、转基因性及乳腺癌骨转移等动物模型,每种动物模型都有各自的特点和应用条件。