Garrulax milnei milnei,a taxon little known in Chinese ornithology

As early as 1874,the French scientist Père A.David introduced to science a new bird species,Trochalopteron milnei,described as:"Ressemblant au T.formosum du Setchouan,mais ayant le dessus de la tête couleur de cannelle ou d’amadou,et la région parotique blanche"(David,1874).The bird skin that Père David collected,and so far deposited in Muséum National d’Histoire Naturelle in Paris,was from"Koaten of W Fo-kien",in the current Chinese romanization system,Koaten is spelt as Guadun and Fo-kien spelt as Fujian.Then,spelling of the specific name of the bird was given as"milni"by David(1875),David and Oustalet(1877),and La Touche(1899,1925–1930).The bird is now usually known as Garrulax milnei milnei.However,Collar and Robson(2007)resurrected the genus Trochalopteron,and this is also being supported by Luo et al.(2009)as well as by Dickinson and Christidis(2014),but Bird Life still uses Garrulax(Bird Life,2015).     

Suitable parameter choice on quantitative morphology of A549 cell in epithelial–mesenchymal transition

Evaluation of morphological changes in cells is an integral part of study on epithelial to mesenchymal transition (EMT), however, only a few papers reported the changes in quantitative parameters and no article compared different parameters for demanding better parameters. In the study, the purpose was to investigate suitable parameters for quantitative evaluation of EMT morphological changes. A549 human lung adenocarcinoma cell line was selected for the study. Some cells were stimulated by transforming growth factor-β1 (TGF-β1) for EMT, and other cells were as control without TGF-β1 stimulation. Subsequently, cells were placed in phase contrast microscope and three arbitrary fields were captured and saved with a personal computer. Using the tools of Photoshop software, some cells in an image were selected, segmented out and exchanged into unique hue, and other part in the image was shifted into another unique hue. The cells were calculated with 29 morphological parameters by Image Pro Plus software. A parameter between cells with or without TGF-β1 stimulation was compared statistically and nine parameters were significantly different between them. Receiver operating characteristic curve (ROC curve) of a parameter was described with SPSS software and F-test was used to compare two areas under the curves (AUCs) in Excel. Among them, roundness and radius ratio were the most AUCs and were significant higher than the other parameters. The results provided a new method with quantitative assessment of cell morphology during EMT, and found out two parameters, roundness and radius ratio, as suitable for quantification.     

虎斑夜鳽分布与亚群态势研究

本世纪以来对虎斑夜鳽分布地点的新发现,表明该种从滨海到内陆漫布于中国长江以南广大地区,并向北渗透直逼东洋界北限秦岭-淮河一线;作者据此将各地的虎斑夜鳽初划为11个亚群,提出目前该种存有3个相对健康而稳定的亚群,即黄山-天目山亚群、南岭亚群和广西亚群,且每个亚群的分布范围均至少不会小于5000km2,其中以黄山-天目山亚群的记录由历史至现今相对最为长久而完整,进而提出今后在上述诸亚群范围之外还会有新的发现.文中指出,尽管近期对虎斑夜鳽分布状况有了新认识,目前仍可视该种的受胁等级为濒危.     

Triple helix-forming oligonucleotides conjugated to new inhibitors of topoisomerase II: synthesis and binding properties

Triplex-forming oligonucleotides (TFOs) are among the most specific DNA ligands and represent an important tool for specific regulation of gene expression. TFOs have also been used to target DNA-modifying molecules to obtain irreversible modifications on a specific site of the genome. A number of molecules have been recognized to target topoisomerase II and stabilize double-stranded cleavage mediated by this enzyme thus determining permanent DNA damage. Among these poisons, etoposide (VP16), a 4'-demethylepipodophyllotoxin derivative, is widely used in cancer chemotherapy. In the aim to design DNA site-specific molecules, three analogues of VP16 (1, 2, and 3), recently described (Duca et al. J. Med. Chem. 2005, 48, 596-603), were attached to TFOs, together with a fourth one, of which the synthesis is reported here. Two different oligonucleotides, differing by the length (a 16-mer and a 20-mer), and two different linker arms between the oligonucleotide and the drug were used. The coupling reaction between the drug and the TFO was further improved. For the first time, we also report the synthesis of TFO conjugates bearing two molecules of inhibitor linked to the same oligonucleotide end. In total, 16 new conjugates were synthesized and evaluated for their ability to form triple helices. The loss in triplex stability due to the conjugation of the TFO to compounds that do not interact with DNA is compensated by the presence of the ethylene glycol linker arm. This stabilization effect is more pronounced at the 3' end than at the 5' end. All conjugates form a stable triplex selectively on the DNA target at 37 degrees C and pH 7.2.     

Interactions between the rabbit CSN1 gene and the nuclear matrix of stably transfected HC11 mammary epithelial cells vary with its level of expression

The expression of casein genes is specific to the mammary gland and maximal during lactation. However, among the numerous mammary cell lines described so far, only a few express some casein genes. The regulatory regions of casein genes have been largely described but the mechanisms explaining the mammary specific expression of these genes, and their silencing in most mammary cell lines, have not yet been fully elucidated. To test the hypothesis that the nuclear location of the casein genes may affect their expression, we transfected HC11 mouse mammary cell line with a 100 kb DNA fragment surrounding the rabbit alpha S1 casein gene. We derived stable clones which express or not the transfected rabbit casein gene, in the same cellular context, independently of the number of transgene copies. Metaphase spreads were prepared from the different clones and the transfected genes were localized. Unexpectedly, we observed that in the original HC11 cell line the number of chromosomes per metaphase spread is close to 80, suggesting that HC11 cells have undergone a duplication event, since the mouse karyotype is 2n = 40. In alpha S1 casein expressing cells, the expression level does not clearly correlate with a localization of the transfected DNA proximal to the centromeres or the telomeres. Analysis of the localization of the transfected DNA in nuclear halos allows us to conclude that when expressed, transfected DNA is more closely linked to the nuclear matrix. The next step will be to study the attachment of the endogenous casein gene in mammary nuclei during lactation.     

Activation of camptothecin derivatives by conjugation to triple helix-forming oligonucleotides

Topoisomerase I (topo I) is a ubiquitous DNA-cleaving enzyme and an important therapeutic target in cancer chemotherapy. Camptothecins (CPTs) reversibly trap topo I in covalent complex with DNA but exhibit limited sequence preference. The utilization of conjugates such as triplex-forming oligonucleotides (TFOs) to target a medicinal agent (like CPT) to a specific genetic sequence and orientation within the DNA has been accomplished successfully. In this study, different attachment points of the TFO to CPT (including positions 7, 9, 10, and 12) were investigated and our findings confirmed and extended previous conclusions. Interestingly, the conjugates induced specific DNA cleavage by topo I at the triplex site even when poorly active or inactive CPT derivatives were used. This suggests that the positioning of the drug in the cleavage complex by the sequence-specific DNA ligand is able to stabilize the ternary complex, even when important interactions between topo I and CPT are disrupted. Finally, certain TFO-CPT conjugates were able to induce sequence-specific DNA cleavage with the topo I mutants R364H and N722S that are resistant to camptothecin. The TFO-CPT conjugates are thus valuable tools to study the interactions involved in the formation of the ternary complex and also to enlarge the family of compounds that poison topo I. The fact that an inactive CPT analogue can act as a topo I poison when appropriately coupled to a TFO provides a new perspective at the level of drug design.     

Position- and orientation-specific enhancement of topoisomerase I cleavage complexes by triplex DNA structures

Topoisomerase I (Top1) activities are sensitive to various endogenous base modifications, and anticancer drugs including the natural alkaloid camptothecin. Here, we show that triple helix-forming oligonucleotides (TFOs) can enhance Top1-mediated DNA cleavage by affecting either or both the nicking and the closing activities of Top1 depending on the position and the orientation of the triplex DNA structure relative to the Top1 site. TFO binding 1 bp downstream from the Top1 site enhances cleavage by inhibiting religation and to a lesser extent DNA nicking. In contrast, TFO binding 4 bp downstream from the Top1 site enhances DNA nicking especially when the 3′ end of the TFO is proximal to the Top1 site. However, when the orientation of the triplex is inverted, with its 5′ terminus 4 bp downstream from the Top1 site, religation is also inhibited. These position- and orientation-dependent effects of triplex structures on the Top1-mediated DNA cleavage and religation are discussed in the context of molecular modeling and effects of TFO on DNA twist and mobility at the duplex/triplex junction.     

Effect of Changes of Temperature Around Roots in Relation to Water Uptake by Roots and Leaf Transpiration

Effects of changes in temperature around roots on water uptake by roots and leaf transpiration were studied in Leucaena leucocephala (Lam.) de Wit., a subtropical woody plant species, and in Zea mays L. When the temperature around roots was rapidly lowered from 25 ℃ to 15 ℃, the water uptake by the roots and leaf transpiration were stimulated significantly within a short period ( 14 min). However, this effect did not occur when the cooling time was prolonged neither did if occur when the temperature around the roots was resumed from 15 ℃ to 25 ℃. Both the hydraulic conductivity of roots and leaf transpiration were increased substantially at first (within 20 min)and then decreased steadily to a level lower than those of the control in which the roots were continuous exposed to a low temperature ( 15 ℃ ). Low temperature also promoted the biosynthesis of ABA in roots and enhanced the xylem ABA concentration, but such stimulation did not occur untill about 30 min after cooling treatment, leaf transpiration was reduced markedly, but the hydraulic conductivity of roots increased when the root system was treated with exogenous ABA. It was suggested that some mechanisms other than ABA may be involved in the short-time cryostimulation of water uptake by roots and leaf transpiration.