A transgenic zebrafish for in vivo visualization of cilia

Cilia are organelles for cellular signalling and motility. Mutations affecting ciliary function are also associated with cilia-related disorders (ciliopathies). The identification of cilia markers is critical for studying their function at the cellular level. Due to the lack of a conserved, short ciliary localization motif, the full-length ARL13b or 5HT₆ proteins are normally used for cilia labelling. Overexpression of these genes, however, can affect the function of cilia, leading to artefacts in cilia studies. Here, we show that Nephrocystin-3 (Nphp3) is highly conserved among vertebrates and demonstrate that the N-terminal truncated peptide of zebrafish Nphp3 can be used as a gratuitous cilia-specific marker. To visualize the dynamics of cilia in vivo, we generated a stable transgenic zebrafish Tg (β-actin: nphp3N-mCherry)^sx1001. The cilia in multiple cell types are efficiently labelled by the encoded fusion protein from embryonic stages to adulthood, without any developmental and physiological defects. We show that the line allows live imaging of ciliary dynamics and trafficking of cilia proteins, such as Kif7 and Smo, key regulators of the Hedgehog signalling pathway. Thus, we have generated an effective new tool for in vivo cilia studies that will help shed further light on the roles of these important organelles.     

Interaction of the anticancer p28 peptide with p53-DBD as studied by fluorescence,FRET, docking and MD simulations

Background

The p28 peptide, derived from the blue copper protein Azurin, exerts an anticancer action due to interaction with the tumor suppressor p53, likely interfering with its down-regulators. Knowledge of both the kinetics and topological details of the interaction, could greatly help to understand the peptide anticancer mechanism.

黄酮和甾体类化合物的抗真菌活性

用琼脂扩散法对从药用植物中分离到的12个黄酮和5个甾体化合物进行了抗真菌活性实验,其中黄芩甙元(baicalein)、funkioside C和胡萝卜甙(daucosterol)对尖孢镰刀菌(Fusarium oxysporum)和白色念珠菌(Candida albicans)的生长均有抑制作用,对尖孢镰刀菌的最低抑菌浓度(MIC)分别为0.112、0.217和0.108g/L,对白色念珠菌的MIC分别为0.264、0.310和0.078g/L。对其构效关系进行了初步讨论。     

Angiogenic activity of syndecan-binding laminin peptide AG73 (RKRLQVQLSIRT)

The AG73 peptide (RKRLQVQLSIRT, mouse laminin alpha 1 chain 2719-2730) promotes cell adhesion and tumor metastasis, and interacts with transmembrane syndecan proteoglycans. Here, we demonstrate AG73 peptide angiogenic activity using in vitro, ex vivo, and in vivo models. AG73 induced murine endothelial cell (SVEC4-10) tube formation on Cultrex Basement Membrane Extract (Cultrex BME) and stimulated sprouting of aortic rings. None of the homologous sequences from the laminin alpha2, alpha3, alpha4, or alpha5 chains was as active as AG73 in promoting sprouting formation. AG73 also mediated angiogenesis in the chick chorioallantonic membrane (CAM) assay. Using subcutaneously injected Cultrex BME supplemented with AG73, we observed a large angiogenic response. Furthermore, AG73-conjugated to a chitosan membrane promoted a strong angiogenic response in the CAM assay. These results indicate that the AG73 peptide is a potent syndecan-binding angiogenesis stimulator and may be useful for therapeutic application to treat ischemic injuries.     

Detecting antimicrobial peptides by exploring the mutual information of their sequences

Abstract

The rise of antibiotic resistance in pathogenic bacteria is a growing concern for every part of the world. The present study shows the prediction efficiency of mutual information for the classification of antimicrobial peptides. The proven role of antimicrobial peptides (AMPs) to fight against multidrug-resistant pathogens and AMP’s low toxic properties laid the foundation of computational methods to play their role in detecting AMPs from non-AMPs. Mutual information vectors (MIV) were created for AMP/non-AMP sequences and then fed to different machine learning classifiers out of which a random forest (RF) classifier showed best results for predicting AMPs. Random forest classifiers were evaluated on benchmark datasets by 10-fold cross-validation. The proposed MIV-RF method showed better prediction accuracy, MCC (Matthews correlation coefficient), and AUC-ROC (Area Under The Curve-Receiver Operating Characteristics) than available methods for detecting AMPs.

Communicated by Ramaswamy H. Sarma     

Hybrid peptides constructed from RES-701-1, an endothelin B receptor antagonist, and endothelin; binding selectivity for endothelin receptors and their pharmacological activity

Hybrid peptides were constructed from endothelin B receptor (ET_B) selective antagonist RES-701-1 (1) and endothelin (ET-1). They have N-terminal 10 amino acids derived from 1 and C-terminal 10 amino acids derived from ET-1. RES-701-1(1-10)-[Ala15]ET-1(12-21) and its analogues substituted or truncated at the residues derived from RES-701-1 had proved to possess high receptor binding activity selective for ET_B as well as 1. Substitutions at the residues derived from ET-1 had produced some analogues that possessed high affinity not only for ET_B but for ET_A. Although all analogues had antagonistic effects on ET_A, some analogues had proved to function as agonist on ET_B confirmed by the changes in intracellular calcium concentrations of ET receptor-transfected COS-7 cells. We have found four types of ET receptor-binding peptides: (1) ET_B-selective agonist with weak ET_A antagonism (3, KT7421); (2) ET_B-selective antagonist with weak ET_A antagonism (29, KT7539); (3) ET_B agonist with potent ET_A antagonism (27, KT7538); and (4) non-selective ET_A/ET_B antagonist (26, KT7540).     

Ridaforolimus体外单独或联合氟康唑抗念珠菌作用的研究

由念珠菌感染引起的侵袭性念珠菌病治疗困难、死亡率高,是临床一大难题。氟康唑是目前治疗该病的一线用药,但近年来耐药菌株逐渐增多,治疗困难。因此,开发新的有效抗真菌药物或发现可提高现有抗真菌药物活性的化合物十分必要。通过体外抗真菌药物敏感性试验,我们发现TOR通路抑制剂ridaforolimus具有抗念珠菌作用。随后我们通过纸片法及微量液基稀释法评价该化合物单独或与氟康唑联合对念珠菌的抗菌效果。结果表明ridaforolimus对念珠菌有杀伤作用,在与氟康唑联合时增强了氟康唑的抗念珠菌能力,逆转了白念珠菌对氟康唑的耐药,并将氟康唑由抑菌剂转化为杀菌剂。本研究为ridaforolimus作为新型抗真菌药及氟康唑增敏剂提供了一定理论基础。     

Non-opioid actions of opioid peptides

Beside the well known actions of opioid peptides on mu-, delta- and kappa-opioid receptors, increasing amount of pharmacological and biochemical evidence has recently been published about non-opioid actions of various opioid peptides. These effects are not abolished by naloxone treatments. Such non-opioid effects are observed both in nervous tissues and in the cellular elements of the immune system. Peptides exhibiting non-opioid effects include beta-endorphin, dynorphin A, nociceptin/OFQ, endomorphins, hemorphins and a number of Proenkephalin A derived peptides, such as Met-enkephalin, Met-enkephalin-Arg-Phe (MERF) and bovine adrenal medullary peptide (BAM22). Non-opioid actions are exerted through different neuronal receptors, e.g., dynorphin hyperalgesia through NMDA receptor, Met-enkephalin induced regulation of cell growth through zeta receptors, pain modulation by nociceptin through ORL-1 or NOP receptors, while BAM22 acts through sensory neuron specific G protein-coupled receptors (SNSR). We have investigated Met-enkephalin-Arg-Phe (MERF) and its analogues by the means of direct and indirect radioligand binding assays. It has been found that in addition to kappa(2) and delta-opioid receptors, MERF can act also through sigma(2)- or probably via FMRF-NH(2) receptors in rat cerebellum. A role of functionally assembling heterodimer receptors in mediating the non-conventional actions of these peptide ligands can not be excluded as well.     

八种菊科中草药抗霉菌及饲料霉变的研究

从我国南方霉变的粮食和饲料中分离得到黄曲霉、黑曲霉等10种霉菌并作为供试菌;采用抑菌圈及二倍稀释法研究了野菊花、艾叶等8种菊科中草药的提取物拮抗此10种供试霉菌的活性．结果表明,蒲公英、虾须草等6种中草药及8种中草药的等比混合品抗霉菌活性最强,对各种供试菌的MIC值均不超过12．5g/L,其中中草药混合品和蒲公英显示了MIC的最小值0．391g／L．对此8种中草药提取物及其混合品抗饲料霉变及黄曲霉毒素的产生做了进一步研究,发现中草药混合品的拮抗霉菌生长及黄曲霉毒素产生的效力很强,对黄曲霉毒素的抑制率可超过95%,显示了广阔的应用前景．     

水稻内生枯草芽孢杆菌G87抗菌蛋白的分离纯化及理化特性

【目的】为得到枯草芽孢杆菌(Bacillus subtilis)G87的抗菌蛋白,明确其蛋白理化特性。【方法】采用硫酸铵沉淀和柱层析法进行分离纯化。【结果】获得单一抗菌活性蛋白(峰6-2-1),此抗菌蛋白分子量为50.8 kDa,等电点为5.90。经初步分析,抗菌蛋白不含脂,而含有少量(0.62%)糖;其蛋白部分具有脯氨酸或羟脯氨酸,但不含芳香族氨基酸。抗菌蛋白在高温(≥60℃)和较碱(pH8)环境下活性明显下降,但较抗紫外线、氯仿和胰蛋白酶、蛋白酶K、胃蛋白酶。【结论】枯草芽孢杆菌G87的抗菌蛋白为不含芳烃的糖蛋白,对高温和碱性条件敏感,而对蛋白酶类和紫外线等不敏感。