Killing cancer with platycodin D through multiple mechanisms

Cancer is a multi‐faceted disease comprised of a combination of genetic, epigenetic, metabolic and signalling aberrations which severely disrupt the normal homoeostasis of cell growth and death. Rational developments of highly selective drugs which specifically block only one of the signalling pathways have been associated with limited therapeutic success. Multi‐targeted prevention of cancer has emerged as a new paradigm for effective anti‐cancer treatment. Platycodin D, a triterpenoid saponin, is one the major active components of the roots of Platycodon grandiflorum and possesses multiple biological and pharmacological properties including, anti‐nociceptive, anti‐atherosclerosis, antiviral, anti‐inflammatory, anti‐obesity, immunoregulatory, hepatoprotective and anti‐tumour activities. Recently, the anti‐cancer activity of platycodin D has been extensively studied. The purpose of this review was to give our perspectives on the current status of platycodin D and discuss its anti‐cancer activity and molecular mechanisms which may help the further design and conduct of pre‐clinical and clinical trials to develop it successfully into a potential lead drug for oncological therapy. Platycodin D has been shown to fight cancer by inducing apoptosis, cell cycle arrest, and autophagy and inhibiting angiogenesis, invasion and metastasis by targeting multiple signalling pathways which are frequently deregulated in cancers suggesting that this multi‐target activity rather than a single effect may play an important role in developing platycodin D into potential anti‐cancer drug.     

Assembly Pathway and Characterization of the RAG1/2-DNA Paired and Signal-end Complexes

Mammalian immune receptor diversity is established via a unique restricted set of site-specific DNA rearrangements in lymphoid cells, known as V(D)J recombination. The lymphoid-specific RAG1-RAG2 protein complex (RAG1/2) initiates this process by binding to two types of recombination signal sequences (RSS), 12RSS and 23RSS, and cleaving at the boundaries of RSS and V, D, or J gene segments, which are to be assembled into immunoglobulins and T-cell receptors. Here we dissect the ordered assembly of the RAG1/2 heterotetramer with 12RSS and 23RSS DNAs. We find that RAG1/2 binds only a single 12RSS or 23RSS and reserves the second DNA-binding site specifically for the complementary RSS, to form a paired complex that reflects the known 12/23 rule of V(D)J recombination. The assembled RAG1/2 paired complex is active in the presence of Mg²⁺, the physiologically relevant metal ion, in nicking and double-strand cleavage of both RSS DNAs to produce a signal-end complex. We report here the purification and initial crystallization of the RAG1/2 signal-end complex for atomic-resolution structure elucidation. Strict pairing of the 12RSS and 23RSS at the binding step, together with information from the crystal structure of RAG1/2, leads to a molecular explanation of the 12/23 rule.     

Statistical shape and appearance models for fast and automated estimation of proximal femur fracture load using 2D finite element models

Estimating the risk of osteoporotic fractures is an important diagnostic step that needs to be taken before medicinal treatment. Densitometry-based criteria are normally used in clinical practice for this purpose. However, densitometry-based techniques could not explain all low-energy fractures. As patient-specific finite element (FE) models allow for consideration of other parameters (e.g. load conditions) that are known to be associated with fracture, they are considered promising candidates for more accurate fracture risk estimation. Nevertheless, they are often time consuming, expensive, and complex to build and may need the type of expertise that is not normally available in clinical settings. In this study, we report the development of an automated platform for estimating proximal femur fracture loads using patient-specific 2D FE models generated using dual-energy x-ray absorptiometry (DXA) scans. First, a statistical shape and appearance model (SSAM) is built using DXA scans of patients screened for osteoporosis following a low energy fracture. SSAM is then used together with Active Appearance Models (AAM) for automated segmentation of the proximal femur from new unseen DXA scans. The mean point-to-curve error of the automated procedure, i.e. 1.2–1.4 mm, is shown to be only slightly larger than the intra-observer variability of manual segmentation, i.e. 1.0 mm. Moreover, the developed platform automatically meshes the segmented shape, assigns density-based mechanical properties, assigns loads and boundary conditions, submits the 2D FE model for solution, and performs post-processing of the 2D FE simulation data to determine fracture loads. The fracture loads predicted using the manually generated and automatically generated 2D FE models are shown to be very close with a mean difference of around 8.8%. Repeated measures ANOVA showed no significant differences between the fracture loads calculated using FE models manually generated by three independent observers and those calculated using the automatically generated FE models (p>0.05).     

The full-length genome analysis of a street rabies virus strain isolated in Yunnan province of China

The epidemic of rabies has rapidly increased and expanded in Yunnan province in recent years.In order to further analyze and understand the etiological reasons for the rapid expansion of rabies in Yunn...     

人Semaphorin 4D慢病毒载体的构建及鉴定

目的:构建并制备能够有效表达Semaphorin 4D的重组慢病毒。方法:从人急性T细胞白血病Jurkat细胞DNA 扩增人Semaphorin 4D基因,克隆至pWPI GW慢病毒载体上,与pVSVG及pSPAX质粒共转染人胚肾293T细胞,包装出重组慢病毒,将纯化后的重组病毒直接感染293T和HUVEC细胞,通过免疫印迹、免疫荧光染色和血管内皮细胞迁移分析等方法检测Semaphorin 4D的表达和诱导血管内皮细胞迁移的作用。结果: 重组慢病毒介导Semaphorin 4D在293T和HUVEC内获得表达,能介导血管内皮细胞迁移。结论:成功构建了表达Semaphorin 4D的重组慢病毒载体。     

大鼠脑缺血再灌注损伤后神经元和星形胶质细胞的动态变化及Cyclin D1表达的差异

目的研究大鼠局灶性脑缺血再灌注损伤后神经元和星形胶质细胞表达量的动态演变及各自cyclin D1的表达差异。方法建立大鼠大脑中动脉阻塞（MCAO）再灌注模型,随机分为再灌注后1d组,3d组,7d组,14d组和假手术组,应用流式细胞术检测各组再灌注后不同时间点神经元和星形胶质细胞数量变化及各自cyclin D1的表达。结果缺血侧梗死边缘区皮质星形胶质细胞的表达增加,而神经元的表达下降,与假手术组比较有明显差异（P〈0．05）;神经元和星形胶质细胞中各自cyclin D1的表达在再灌注7d、14d后表达上调,且星形胶质细胞中的cyclinD1增加更明显,与假手术组比较有统计学差异（P〈0．05）。结论大鼠脑缺血再灌注后,缺血侧梗死边缘区皮质星形胶质细胞和神经元的cyclinD1表达均有不同程度的上调,星形胶质细胞的cyclin D1表达上调比神经元的更为显著。     

Mandibular Shape, Ontogeny and Dental Development in Bonobos (Pan paniscus) and Chimpanzees (Pan troglodytes)

The postnatal ontogenetic patterns and processes that underlie species differences in African ape adult mandibular morphology are not well understood and there is ongoing debate about whether African ape faces and mandibles develop via divergent or parallel trajectories of shape change. Using three-dimensional (3D) morphometric data, we first tested when in postnatal development differences in mandibular shape are initially evident between sister species Pan troglodytes and P. paniscus. Next, we tested whether each species has a distinct and non-parallel trajectory of mandibular development. Mandibles sampled across a broad developmental range of wildshot bonobos (n = 44) and chimpanzees (n = 59) were radiographed and aged from their dental development. We then collected 3D landmark surface data from all the mandibles. A geometric morphometric analysis of size-corrected 3D data found that bonobos and chimpanzees had parallel and linear ontogenetic trajectories of mandibular shape change. In contrast, mandibular shape was statistically different between P. paniscus and P. troglodytes as early as infancy, suggesting that species shape differences are already established near or before birth. A linear and stable trajectory of shape change suggests that mandibular ontogeny in these apes is unimpacted by non-linear variation in tooth developmental timing.     

Production and physicochemical characterization of acidocin D20079, a bacteriocin produced by Lactobacillus acidophilus DSM 20079

Lactobacillus acidophilus DSM 20079 is the producer of a novel bacteriocin termed acidocin D20079. In this paper, a partial sequence of this peptide is determined, together with data on its secondary structure. A modification of the MRS-growth medium (replacing the detergent Tween 80 with oleic acid), was shown to improve the production level of the peptide by one order of magnitude, as well as to stabilize the activity level. Addition of a detergent (Tween 20, less interfering in mass spectrometric analysis), was however necessary for solubilization of the purified acidocin D20079. Digestion of the peptide followed by de-novo sequencing of generated fragments, allowed determination of a partial sequence consisting of 39 of the totally estimated 65 residues. Acidocin D20079 has a high content of glycine residues, hydrophobic residues, and acidic residues. No modified amino acids were found. Edman degradation, and C-terminal sequencing failed, suggesting that the peptide may be cyclic, and a novel member of class IIc bacteriocins. Circular dichroism spectroscopy and secondary structure prediction showed random coil conformation in aqueous solution, but secondary structure was induced in the presence of sodium-dodecyl sulfate. The data could be fitted assuming 2–13% of the residues to be in α-helix and 23–27% of the residues to be in β-strand conformation. This indicates that a membrane/membrane-mimicking hydrocarbon–water interface induces an active conformation.     

Insights into the function of PsbR protein in Arabidopsis thaliana

The functional state of the Photosystem (PS) II complex in Arabidopsis psbR T-DNA insertion mutant was studied. The ΔPsbR thylakoids showed about 34% less oxygen evolution than WT, which correlates with the amounts of PSII estimated from Y_D^ox radical EPR signal. The increased time constant of the slow phase of flash fluorescence (FF)-relaxation and upshift in the peak position of the main TL-bands, both in the presence and in the absence of DCMU, confirmed that the S₂Q_A⁻ and S₂Q_B⁻ charge recombinations were stabilized in ΔPsbR thylakoids. Furthermore, the higher amount of dark oxidized Cyt-b559 and the increased proportion of fluorescence, which did not decay during the 100s time span of the measurement thus indicating higher amount of Y_D⁺Q_A⁻ recombination, pointed to the donor side modifications in ΔPsbR. EPR measurements revealed that S₁-to-S₂-transition and S₂-state multiline signal were not affected by mutation. The fast phase of the FF-relaxation in the absence of DCMU was significantly slowed down with concomitant decrease in the relative amplitude of this phase, indicating a modification in Q_A to Q_B electron transfer in ΔPsbR thylakoids. It is concluded that the lack of the PsbR protein modifies both the donor and the acceptor side of the PSII complex.