Sarracenia alata (Alph.Wood) Alph.Wood Microcuttings as a Source of Volatiles Potentially Responsible for Insects’ Respond

Rare carnivorous plants representing the genus Sarracenia are perceived as very interesting to scientists involved in various fields of botany, ethnobotany, entomology, phytochemistry and others. Such high interest is caused mainly by the unique capacity of Sarracenia spp. to attract insects. Therefore, an attempt to develop a protocol for micropropagation of the Sarracenia alata (Alph.Wood) Alph.Wood, commonly named yellow trumpets, and to identify the specific chemical composition of volatile compounds of this plant in vitro and ex vivo was undertaken. Thus, the chemical volatile compounds excreted by the studied plant to attract insects were recognized with the application of the headspace solid-phase microextraction (HS-SPME) coupled with the GC-MS technique. As the major volatile compounds (Z)-3-hexen-1-ol (16.48% ± 0.31), (E)-3-hexen-1-ol acetate (19.99% ± 0.01) and β-caryophyllene (11.30% ± 0.27) were identified. Further, both the chemical assumed to be responsible for attracting insects, i.e., pyridine (3.10% ± 0.07), and whole plants were used in in vivo bioassays with two insect species, namely Drosophila hydei and Acyrthosiphon pisum. The obtained results bring a new perspective on the possibilities of cultivating rare carnivorous plants in vitro since they are regarded as a valuable source of bioactive volatile compounds, as including ones with repellent or attractant activity.     

Micro-optical Characterization of Fluidic Self-assembly of Drosophila Embryos through Surface Tension: Principle, Simulation and Experiments

We describe high precision experimental and numerical characterization of the positioning forces acting on Drosophila embryos that have self-assembled onto two-dimensional arrays of hydrophobic sites on a silicon substrate in water. The forces measured using a surface micromachined optical-encoder force sensor operating in reflection, are in good agreement with numerical simulations based on an extended surface energy model for the oil-based fluidic system. The positioning forces of ellipsoidal embryos on flat pads show a linear-spring-like relationship between the force and displacement on rectangular as well as cross-shaped pads. In contrast, the positioning forces of flat silicon chips, similar in size to the embryos, are linear in the displacement only over a limited range, and are then constant up to the detachment force. The optical force characterization method and the associated surface energy model for the self-assembly process can potentially be used for design optimization of fluidic self-assembly for a wide range of applications in biology.     

Insect pheromones and their analogs. LX. Stereocontrolled synthesis of sex pheromones ofDrosophila mulleri andMayetiola destructor

Syntheses are developed for 2S-tridecyl- and 2S-tridec-10E-enylacetates, sex pheromones of the fruit flyDrosophila mulleri and the Hessian flyMayetiola destructor, respectively, that are based on ethyl-3S-hydroxybutanoate, a product from enzymatic reduction of ethyl acetoacetate by the soil yeast strain 80-1.Work performed under the auspices of the Federal program Integratsiya of the RF (Contract No. A 0005).Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 167–169, March–April, 2000.     

果蝇heix基因启动子的分析及其转录活性鉴定

采用生物信息学的方法,综合运用启动子预测工具Promotor Scan1.7和BDGP(neural network pro-moter prediction)分析了目标序列的启动子特征,以果蝇基因组DNA为模板扩增出heix基因启动子候选序列连接至pMD19T载体,构建了荧光素酶报道基因重组质粒pHeixpromoter-Luc,转染果蝇S2细胞表达荧光素酶,并测定了荧光素酶的活性.预测出4个候选的heix基因启动子序列,发现存在ATF、MLTF、c-fos_US5等多种转录因子调控基序;成功构建了pMD19T-Heixpromoter和pHeixpromoter-Luc重组质粒.与肌动蛋白启动子(actinp romoter)相比,pHeixpromoter-Luc表达出的荧光素酶也有较强的活性.本研究找到了果蝇heix基因启动子候选序列,并发现多种转录调控元件,其荧光素酶报告基因实验说明果蝇heix基因启动子与肌动蛋白启动子有相当的转录活性.     

On the performance of bioanalytical fluorescence correlation spectroscopy measurements in a multiparameter photon-counting microscope

Fluorescence correlation spectroscopy (FCS) data acquisition and analysis routines were developed and implemented in a home-built, multiparameter photon-counting microscope. Laser excitation conditions were investigated for two representative fluorescent probes, Rhodamine110 and enhanced green fluorescent protein (EGFP). Reliable local concentrations and diffusion constants were obtained by fitting measured FCS curves, provided that the excitation intensity did not exceed 20% of the saturation level for each fluorophore. Accurate results were obtained from FCS measurements for sample concentrations varying from pM to μM range, as well as for conditions of high background signals. These experimental constraints were found to be determined by characteristics of the detection system and by the saturation behavior of the fluorescent probes. These factors actually limit the average number of photons that can be collected from a single fluorophore passing through the detection volume. The versatility of our setup and the data analysis capabilities were tested by measuring the mobility of EGFP in the nucleus of Drosophila cells under conditions of high concentration and molecular crowding. As a bioanalytical application, we studied by FCS the binding affinity of a novel peptide-based drug to the cancer-regulating STAT3 protein and corroborated the results with fluorescence polarization analysis derived from the same photon data.     

Fertility and Iron Bioaccumulation in Drosophila melanogaster Fed with Magnetite Nanoparticles Using a Validated Method

Research on nanomaterial exposure-related health risks is still quite limited; this includes standardizing methods for measuring metals in living organisms. Thus, this study validated an atomic absorption spectrophotometry method to determine fertility and bioaccumulated iron content in Drosophila melanogaster flies after feeding them magnetite nanoparticles (Fe₃O₄NPs) dosed in a culture medium (100, 250, 500, and 1000 mg kg⁻¹). Some NPs were also coated with chitosan to compare iron assimilation. Considering both accuracy and precision, results showed the method was optimal for concentrations greater than 20 mg L⁻¹. Recovery values were considered optimum within the 95–105% range. Regarding fertility, offspring for each coated and non-coated NPs concentration decreased in relation to the control group. Flies exposed to 100 mg L⁻¹ of coated NPs presented the lowest fertility level and highest bioaccumulation factor. Despite an association between iron bioaccumulation and NPs concentration, the 500 mg L⁻¹ dose of coated and non-coated NPs showed similar iron concentrations to those of the control group. Thus, Drosophila flies’ fertility decreased after NPs exposure, while iron bioaccumulation was related to NPs concentration and coating. We determined this method can overcome sample limitations and biological matrix-associated heterogeneity, thus allowing for bioaccumulated iron detection regardless of exposure to coated or non-coated magnetite NPs, meaning this protocol could be applicable with any type of iron NPs.