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Optimal Medium (optimal + medium)
Selected AbstractsOptimization of culture conditions for plant regeneration of Panicum spp. through somatic embryogenesisGRASSLAND SCIENCE, Issue 1 2010Mi-Suk Seo Abstract We developed a rapid and efficient shoot regeneration system for Panicum spp. by adjusting the regeneration medium and studying the responses of different genotypes and the influence of explant types (mature seed, immature embryo and shoot apex). We used Panicum meyerianum (Nees) and Panicum longijubatum (Stapf) which were shown to perform well, to select the optimal medium for shoot regeneration. The highest frequency of shoot regeneration was obtained on Murashige and Skoog medium supplemented with 30 g L,1 maltose and 1 mg L,1 N-phenyl-N,-[(1,2,3-thidiazol-5-yl) urea]. The callus formed green spots after 1 week of culture and showed primary green shoots after 2 weeks. In this system, the calli derived from mature seed of nine Panicum genotypes showed large variation in shoot regeneration ability: from 0 to 69.9% in the frequency of shoot formation and from 0 to 8.4 in the number of shoots per callus. Guineagrass (Panicum maximum Jacq.) showed no ability and switchgrass (Panicum virgatum L.) showed low ability to regenerate from mature seed-derived calli; however, both were able to be regenerated from immature embryos and calli derived from shoot apices. We developed an efficient protocol for high shoot regeneration of various Panicum genotypes which provides a foundation for efficient tissue culture and genetic improvement of Panicum. [source] Optimization of a medium for enhancing nicotine biodegradation by Ochrobactrum intermedium DN2JOURNAL OF APPLIED MICROBIOLOGY, Issue 3 2006Y.J. Yuan Abstract Aims:, To optimize a medium for nicotine degradation by Ochrobactrum intermedium DN2 in presence of yeast extract, glucose and Tween 80 using response surface methodology (RSM). Methods and Results:, In this study, the effects of yeast extract, glucose and Tween 80 on nicotine degradation were investigated in flasks using a novel nicotine-degrading bacterium, O. intermedium DN2. A full factorial central composite design was applied in the design of experiments and in the analysis of the experimental data. The results showed that the most significant variable influencing nicotine degradation was yeast extract, followed by glucose, and then Tween 80. Moreover these three factors interacted with each other and combined to produce positive effects on nicotine degradation. The experimental data also allowed the development of an empirical model (P < 0·0001) describing the inter-relationship between independent and dependent variables. By solving the regression equation, the optimal values of the variables were determined as: yeast extracts 0·094%, glucose 0·101% and Tween 80 0·080%. Using the medium obtained, about 1220 mg l,1 of nicotine was degraded (95·55%) within 10 h at the specific biodegradation of 116·59 mg l,1 h,1 in 30-l bioreactor containing 25-l tobacco extract. Conclusions:, An optimal medium of nicotine degradation by the strain DN2 was obtained. Significance and Impact of the Study:, RSM proved to be reliable in developing the model, optimizing factors and analysing interaction effects. The results provide better understanding on the interactions between yeast extract, glucose and Tween 80 for nicotine biodegradation. [source] The Stability of Collected Human Scent Under Various Environmental Conditions,JOURNAL OF FORENSIC SCIENCES, Issue 6 2009Davia T. Hudson Ph.D. Abstract:, Human scent evidence collected from objects at a crime scene is used for scent discrimination with specially trained canines. Storage of the scent evidence is usually required yet no optimized storage protocol has been determined. Storage containers including glass, polyethylene, and aluminized pouches were evaluated to determine the optimal medium for storing human scent evidence of which glass was determined to be the optimal storage matrix. Hand odor samples were collected on three different sorbent materials, sealed in glass vials and subjected to different storage environments including room temperature, ,80°C conditions, dark storage, and UVA/UVB light exposure over a 7-week period. Volatile organic compounds (VOCs) in the headspace of the samples were extracted and identified using solid-phase micro-extraction,gas chromatography/mass spectrometry (SPME,GC/MS). Three-dimensional covariance mapping showed that glass containers subjected to minimal UVA/UVB light exposure provide the most stable environment for stored human scent samples. [source] Facile High-Yield Synthesis of Polyaniline Nanosticks with Intrinsic Stability and Electrical ConductivityCHEMISTRY - A EUROPEAN JOURNAL, Issue 33 2008Xin-Gui Li Prof. Abstract Chemical oxidative polymerization at 15,°C was used for the simple and productive synthesis of polyaniline (PAN) nanosticks. The effect of polymerization media on the yield, size, stability, and electrical conductivity of the PAN nanosticks was studied by changing the concentration and nature of the acid medium and oxidant and by introducing organic solvent. Molecular and supramolecular structure, size, and size distribution of the PAN nanosticks were characterized by UV/Vis and IR spectroscopy, X-ray diffraction, laser particle-size analysis, and transmission electron microscopy. Introduction of organic solvent is advantageous for enhancing the yield of PAN nanosticks but disadvantageous for formation of PAN nanosticks with small size and high conductivity. The concentration and nature of the acid medium have a major influence on the polymerization yield and conductivity of the nanosized PAN. The average diameter and length of PAN nanosticks produced with 2,M HNO3 and 0.5,M H2SO4 as acid media are about 40 and 300,nm, respectively. The PAN nanosticks obtained in an optimal medium (i.e., 2,M HNO3) exhibit the highest conductivity of 2.23,S,cm,1 and the highest yield of 80.7,%. A mechanism of formation of nanosticks instead of nanoparticles is proposed. Nanocomposite films of the PAN nanosticks with poly(vinyl alcohol) show a low percolation threshold of 0.2,wt,%, at which the film retains almost the same transparency and strength as pure poly(vinyl alcohol) but 262,000 times the conductivity of pure poly(vinyl alcohol) film. The present synthesis of PAN nanosticks requires no external stabilizer and provides a facile and direct route for fabrication of PAN nanosticks with high yield, controllable size, intrinsic self-stability, strong redispersibility, high purity, and optimizable conductivity. [source] | ||||||||||