低温对东方百合试管鳞茎解除休眠及生长的影响

以东方百合‘索邦’和‘西伯利亚’鳞片为外植体得到的一代试管小鳞茎为试材,研究0℃冷藏不同时间对试管鳞茎生理指标变化,以及试管鳞茎解除休眠和移栽后生长发育的影响。结果表明,冷藏0--28dN,随着冷藏时间的延长,试管鳞茎出苗率逐渐增加,冷藏处理28d达到最高,之后逐渐降低。冷藏期间,试管鳞茎中淀粉含量持续降低,而可溶性总糖和还原性糖含量表现出先升高后下降的趋势,冷藏处理28d的含量最高。同时,随着冷藏时间的延长,IAA和ZR含量逐渐升高,ABA含量逐渐下降,而GA。含量表现出先上升后下降的趋势,并且也在冷藏处理28dN-含量达到峰值。另外,采用隶属函数值对低温处理的试管苗栽培1年后所收获种球的数量、质量等指标进行评价,结果显示,均以低温处理28d时达到最大值。由此得出,0℃低温处理试管小鳞茎28d为解除休眠及促进生长发育的最适处理时间。     

‘香槟’月季的组织培养和试管开花诱导

本文对‘香槟’月季（80sachinensis‘Xiangbin’）的组织培养技术和诱导试管开花进行了研究。结果表明：以茎段为外植体能诱导获得无菌苗,适宜的启动培养基为MS＋6-BA1．0mg-L-1＋IBA0．1mg·L-1,幼芽继代增殖的最佳培养基是MS＋6．BA1．0mg·L-1。＋IBA0．1～0．2mg·L-1,诱导生根的适宜培养基为1／2MS＋NAA0．3mg·L-1,生根率达80．0％。诱导试管开花的适宜培养基为MS＋6．BA0．5mg·L-1＋NAA0．1mg·L-1最适宜的诱导试管开花的蔗糖含量是30g·L-1;在三角瓶中培养,试管花可以正常开放,在培养瓶中培养花芽不能正常开放;MS培养基中增加2倍磷的含量,可以提高花芽诱导率,为25．O％;诱导试管开花的最适培养条件为温度21℃,光照强度80～100μmol·m-2．s-1,光照时间16h—d-1。     

The largest European lion Panthera leo spelaea (Goldfuss 1810) population from the Zoolithen Cave,Germany: specialised cave bear predators of Europe

Remains of 13 individuals with 3/1 male/female ratio of the extinct Upper Pleistocene lion Panthera leo spelaea (Goldfuss, 1810) from the Zoolithen Cave near Burggeilenreuth (Bavaria, Germany) include the holotype skull and all paratype material. The highest mortality rate for the Zoolithen Cave lions is in their reproductive adult ages. Bite marks on lion bones or skulls are results of hyena activities, or rare cannibalism of lions under stress situations. Lions were possibly also killed in battles with cave bears during predation on hibernating bears in winter times. This cave bear hunt specialisation in caves overlaps with the ecological behaviour of cave bear feeding by Ice Age-spotted hyenas. Both largest Ice Age predators, lions and hyenas, had to specialise on feeding herbivorous cave bears in boreal forest mountainous cave rich regions, where the mammoth steppe megafauna prey was absent. This cave bear hunt by felids, and scavenging by hyenas and other large carnivores such as leopards and wolves explains why cave bears hibernated deep in to the European caves, for protection reasons against predators. Within such lion–cave bear and even lion–hyena conflicts in the caves lions must have been killed sometimes, explaining mainly the skeleton occurrences in different European caves.     

Molecular Dynamics Simulations of Proteins in Water Without the Truncation of Long-range Coulomb Interactions

A new program package (COSMOS90) for molecular dynamics simulations was developed to simulate large molecular systems consisting of more than tens of thousands of atoms without the truncation of long-range coulomb interactions. This program package was based on a new approximation scheme (PPPC) for calculating efficiently the coulomb interactions without sacrificing accuracy. In this approximation scheme, the group of charges at a long distance from each atom was represented by a total charge and total dipole moment of the group. In order to assess the accuracy of PPPC and the ability of COSMOS90, molecular dynamics simulations were carried out for a large system consisting of 16108 atoms (human lysozyme in water) for 50 ps using this program package. The coulomb energy per solute atom was calculated with only five percent of the error found in the 10 Å cut-off approximation (about 0.9 kcal/mol versus 18 kcal/mol, respectively). The molecular dynamics simulations using COSMOS90 require no more CPU time than the simulations based on the 10 Å cut-off approximation of the conventional programs for macromolecular simulations.     

UVC fluencies for preventative treatment of Pseudomonas aeruginosa contaminated polymer tubes

Exposing Pseudomonas aeruginosa biofilm grown on the inner surface of Teflon and silicone tubes to UVC light (265 nm) from light emitting diodes (LED) has previously been shown to substantially reduce biofilm growth. Smaller UVC fluencies were required to disinfect Teflon tubes compared to silicone tubes. Light propagation enhancement in tubes can be obtained if the refractive index of the intra-luminal saline solution is higher than that of the polymer. This condition is achieved by using Teflon tubes with a low refractive index (1.34) instead of the polymers with a high refractive index (1.40–1.50) normally used for tubing in catheter production. Determining whether or not UVC light exposure can disinfect and maintain the intra-luminal number of colony forming units (CFUs) at an exceedingly low level and thus avoid the growth and establishment of biofilm is of interest. The use of UVC diodes is demonstrated to be a preventative disinfection treatment on tubes made of Teflon, which enhances the UVC light propagation, and on tubes made of a softer material, ethylene vinyl acetate (EVA), which is suitable for catheters but much less suitable for UVC light propagation. Simulating an aseptic breach (～10³–10⁴ CFU ml^?1), the UVC disinfection set-up was demonstrated using tubes contaminated with planktonic P. aeruginosa. After the tubes (10–20 cm) were inoculated with the bacterial solution for 3 h, they were emptied and filled with saline solutions (0.9–20%). Next UVC fluencies (0–21 mJ cm^?2) were applied to the tubes 3 h after inoculation. Colony counts were carried out on liquid samples drawn from the tubes the first day after UVC treatment and liquid and surface samples were collected and analyzed 3–4 days later. A fluence of approximately 1.0 mJ cm^?2 was noted as being sufficient for no growth for a period of 3–4 days for the Teflon tubes. Determining the fluence threshold for the EVA tubes was not possible. Almost all of the UVC-treated EVA tubes were disinfected simply by filling the tubes with a saline solution. Direct UVC treatment of the contaminated EVA tubes revealed, however, that a fluence of 21 mJ cm^?2 killed the bacteria present in the tubes and kept them disinfected for a period of 3–4 days.     

On the Application of Widom's Test Particle Method to Homogeneous and Inhomogeneous Fluids

Abstract

Chemical potentials of a homogeneous and an inhomogeneous Lennard-Jones fluid have been determined by molecular dynamics simulations on the vector computer CYBER 205 by applying essentially the fictitious test particle method of Widom. For the homogeneous fluid we find, contrary to the previous result of Guillot and Guissani, that the simulated chemical potential is independent of the particle number. The crucial point, however, is a sufficiently large cut-off radius in the evaluation of the Boltzmann factor. Comparing with our WCA-type perturbation theory, we get agreement in the chemical potentials within 0.1 kT up to the density n[sgrave]³ = 0.80 and a difference of 0.2 kT at n[sgrave]³ = 0.85. For the inhomogeneous case we consider a fluid in a cylindrical pore and integrate Widom's equation over a certain probe volume as suggested earlier by us. Chemical potentials are then calculated independently in five different probe volumes, which are cylindrical shells. The results agree well from the second to the fourth shell. Inaccuracies in the innermost cylinder can be easily explained by bad statistics. In the shell close to the wall the extremely high local density is responsible for the inaccuracies. Extending the probe volume over all cylindrical shells besides the one closest to the wall is thought to yield rather reliable results for the chemical potential. As a by-product of the simulations we also obtained diffusion coefficients, which are given in an appendix.     

Combined strategies for liposome characterization during in vitro digestion

Three types of pyranine (HPTS)-containing liposomes were prepared by high-pressure homogenization under optimized conditions. At 37°C, they were 1) fluid-state vesicles made from soybean phosphatidylcholine (SPC), 2) gel-state liposomes made from hydrogenated SPC (HSPC), and 3) solid-disordered membranes obtained from HSPC and cholesterol (HSPC-Chol). These liposome formulations were characterized before, during, and after in vitro digestion, which involved the presence of pH gradients, enzymes, and bile salts. Mean sizes and size distributions of the vesicles were determined by DLS; ³¹P-NMR (nuclear magnetic resonance) was used to quantify lyso-PC forms; internal pH was monitored throughout digestion with two different fluorescent pH probes; and changes in bilayer permeability and HPTS encapsulation were determined by size-exclusion chromatography and fluorimetry. Differential scanning calorimetry analysis was also performed in order to study the effect of digestion on HSPC vesicles. SPC liposomes were physically stable during digestion; they presented 8% lyso-forms and an HPTS encapsulation around 85% after in vitro digestion. However, they were extremely permeable to ions, so that the internal pH immediately equilibrated with the bulk pH. HSPC liposomes were the most affected by the digestive process. Even though they were chemically stable, as inferred from the low lyso-PC content, very important changes in their size distribution were observed. A final 50% HPTS leakage was quantified after in vitro digestion. Nevertheless, they were the least permeable to protons under pH gradients. HSPC-Chol vesicles presented intermediate permeability to protons, having their internal pH decreased from approximately 6.8 to 4.6 after 1 hour of incubation at pH 2. This was the most chemically stable formulation and showed the highest encapsulation, even after in vitro digestion. Therefore, HSPC-Chol liposomes would be the most adequate choice for the design of lipid products for oral administration.     

Enantioselective Separation and Simultaneous Determination of Tolperisone and Eperisone in Rat Plasma by LC‐MS/MS

Tolperisone and eperisone used as muscle relaxants possess one chiral center each and exist as two optical isomers for each drug. Therefore, enantioselective assays to measure each enantiomer in biological matrices are of great importance. In the present study a simple and complete reverse‐phase liquid chromatography tandem mass spectrometric method for separation and enantioselective determination of tolperisone and eperisone in rat plasma was developed. The analytes were extracted from rat plasma by a simple protein precipitation method with acetonitrile as the extraction solvent. The enantioselective separation of analytes was achieved on a Cellulose Tris (4‐chloro‐3‐methylphenylcarbamate) chiral column with a mobile phase of acetonitrile: 10 mM ammonium acetate in an isocratic mode of elution and mass spectrometric detection. The calibration curve for each enantiomer was found to be linear over 0.2 to 20 ng/mL for each enantiomer. The proposed method exhibited good intra‐ and interday precision (% CV) ranged between 0.95–6.05% and 1.11–8.21%, respectively. The intra‐ and interday accuracy for the proposed assay method ranged between 94.0–100.5% and 92.7–102.1%, respectively. The proposed method was validated as per regulatory guidelines. Chirality 25:622–627, 2013. © 2013 Wiley Periodicals, Inc.     

Biotechnological Production of Plant-Based Insecticides

ABSTRACT:?

The demand for natural and nonpersistent insecticides is increasing day by day. Plant cell cultures could be an alternative to conventional methods of production of insecticides from field-grown plants. In vitro cultured plant cells produce a wide array of insecticides as a part of their secondary metabolism. Their ability to synthesize key enzymes and the manipulation of these could lead to the enhanced production of many insecticides of industrial importance. The development of a high-yielding hairy root culture system for thiophenes, nicotine, and phytoecdysones is of considerable interest. In this article, the current literature on various factors that influence the growth, production, and secretion of six insecticidal compounds, namely, pyrethrins, azadirachtin, thiophenes, nicotine, rotenoids, and phytoecdysones which have been prospects for the scale-up of cell cultures, genetic engineering to obtain transgenic plants, and metabolically engineered plants for increased production of bio-molecules, has been discussed. Environmental safety clearance and the future prospects of application of bio-molecules for plant-derived insecticides are presented.     

Conformations Consistent with Charge Migration Observed in DNA and RNA X-ray Structures

Abstract

Electron holes are known to migrate along the DNA or RNA duplexes and to localize preferentially on successive guanines. The stationary point conformations of Gua pairs that can trap or let pass these holes have been characterized by quantum chemistry calculations. Here we show their recurrent occurrence in DNA and RNA X-ray structures, often in quadruplex conformations or in interaction with proteins, ligands or metal ions. These findings give support to the biological, possibly regulatory, roles of charge migration in cell functioning.