76 Georgia Tech Researchers Apply DLS in Novel Way to Predict Protein Aggregation
Researchers at the Georgia Institute of Technology School of Chemical and Biomolecular Engineering are using the simple to use technique of dynamic light scattering (DLS) measurements to predict otherwise difficult-to-measure aggregation behaviors in proteins. Using the Zetasizer Nano from Malvern Instruments, the Georgia Tech team measures small volumes of stable protein solutions with low concentrations of different salts. From the results they can infer ion-specific trends in the kinetics of aggregation induced by much higher concentrations of the same salts. Such trends, derived from the analysis of non-aggregating samples, could be confirmed experimentally in rapidly aggregating samples of the same protein.
Associate Professor Sven Holger Behrens, said: “We use the Malvern Zetasizer DLS option in two ways in our protein studies. The first is a common approach and records the change in hydrodynamic radius (particle size) that occurs as proteins aggregate. Our second, more novel technique, is to look at non-aggregating protein solutions with the same types of salt-ions but much lower salt concentrations. These low salt solutions remain stable for as long as we look at them and we have found that protein interactions in these solutions, visible in DLS as a change in diffusivity (or apparent particle size) with protein concentration, correlate strongly with aggregation stability at much higher concentrations and can therefore predict ion- specific aggregation trends in proteins.”
“What makes the Malvern Zetasizer nice is its user friendliness – it takes my students little time to familiarise themselves with this instrument. The fact that you can make these measurements in relatively small sample volumes, facilitated by cuvettes also supplied by Malvern, is also very helpful, as is the instrument’s convenient temperature control.” With co-authors Professor Andreas Bommarius and graduate students Jonathan Rubin and Adriana San Miguel, Professor Behrens published the results of his study titled ‘Correlating Aggregation Kinetics and Stationary Diffusion in Protein- Sodium Salt Systems Observed with Dynamic Light Scattering’ in the Journal of Physical Chemistry B. Malvern’s Zetasizer series measures particle and molecular size from below one nanometer to several microns, zeta potential, electrophoretic mobility, and molecular weight.
Circle no. 237
New Reaction Station Improves the Productivity of your Chemistry
New High-Intensity LED Light Transilluminator
Syngene is delighted to introduce the UltraSlim-LED blue light transilluminator, a high-intensity LED light transilluminator, which allows scientists safe, sensitive viewing of a wide range of fluorescently stained DNA/RNA gels. The compact UltraSlim-LED transilluminator uses LEDs to produce an Epi-blue light with a narrow emission peak centred at 470nm. This is not only safer but is comparable to UV for the excitation of most fluorescent dyes, including Ethidium bromide, GelRed, GelGreen, SYBR Gold, SYBR Green, SYBRSafe, and Syngene’s new UltraPower DNA safe dye.
The UltraSlim-LED can be used as a portable transilluminator on the bench as the system is easy to lift, takes up very little bench space and scientists do not have to worry about stray UV light causing retinal and skin damage. The transilluminator is also compatible with any Syngene gel documentation system, allowing users to produce high quality images for publication or analysis. The transilluminator features a special built-in glass filter lid, providing optimum viewing conditions for band cutting. Additionally, since LED illumination is not as damaging to DNA as UV, even after long exposure times, scientists could improve the cloning efficiency of DNA fragments they extract from gels viewed on an UltraSlim-LED transilluminator.
Laura Sullivan, Syngene’s Divisional Manager, stated: “Isolating DNA is probably among the most basic things molecular biologists regularly do and we are pleased to introduce our UltraSlim-LED illuminator as it offers a way of safely viewing stained gels, either on the lab bench or inside a gel doc system.”
Laura concluded: “Using high-intensity blue light eliminates the dangers of using UV, does not damage DNA fragments and yet illuminates even the faintest of bands. This makes the UltraSlim-LED transilluminator an essential purchase for molecular biologists wanting safe, effective imaging of their fluorescent gels.”
Radleys has announced a new and improved version of their popular Carousel 6 Reaction Station - the world's favourite parallel synthesiser.
The Carousel 6 Plus Reaction Station has been designed to provide chemists with an easy to use productivity tool that simultaneously heats and/or cools, stirs and refluxes up to six round bottom flasks from 5ml to 250ml under an inert atmosphere. The Carousel 6 Plus is ideal for all popular solution phase and solid phase syntheses.
The new streamline Carousel 6 Plus features chemically resistant, push on PTFE caps for rapid connection to the radial gas system, without the need for tubing. Plus the caps also feature a new quick-thread that simplifies the attachment of the caps to a wide range of glassware.
An expanded range of round bottom, glass reaction vessels now includes improved wide neck flasks, suitable for use with PTFE stirrer paddles, Azeotropic flasks, baffled flasks for improved mixing and an expanded range of plain and sidearm flasks, from 5ml to 250ml. The new Carousel 6 Plus also delivers better flask-to-flask temperature uniformity and faster heating to 180ºC, both critical for effective parallel chemistry. The Carousel 6 Plus can be further upgraded with the addition of the Tornado system to provide powerful, overhead mechanical stirring; ideal for viscous samples and for the dispersion of delicate solids in solution. The Breeze and Storm heating/cooling modules combine with the Carousel 6 Plus and a suitable circulator to provide controlled heating/cooling from -65ºC to +200ºC. Ideal for crystallization studies and other applications requiring controlled temperature profiles.
Circle no. 240
Circle no. 238
Cost-Effective Determination of Inorganic Anions and Cations in Municipal Drinking Water
Thermo Fisher Scientific, Inc is pleased to announce a new application demonstrating the separation of common inorganic anions and cations in municipal drinking water samples on the capillary Thermo Scientific Dionex IonPac AS19 hydroxide- selective anion-exchange column and the Thermo Scientific Dionex IonPac CS12A columns using electrolytically generated eluent. The analytes were detected by suppressed conductivity using the Thermo Scientific Dionex Capillary Electrolytic Suppressors (CESTM Reagent-Free IC (RFICTM
) and the capillary Thermo Scientific Dionex ICS-5000 ) IC system.
Application Brief 133, Cost-effective Determination of Inorganic Anions and Cations in Municipal Drinking Water using Capillary Ion Chromatography, should be of interest to municipal water companies and other companies determining inorganic anions and cations in simple-matrix environmental samples. Capillary IC systems can be left on and ready for analysis at any time, maintaining stability and requiring less frequent calibrations, thus reducing analysis time and increasing throughput. The amount of waste generated is significantly decreased and the eluent generation cartridge producing the eluent lasts 18 months under continuous operation mode, reducing overall cost of ownership.
Circle no. 239
New Design, New Features
Pol-Eko-Aparatura sp.j have presented a new, refreshed range of their thermostatic equipment. This new ‘GRAPHITE’ range of ovens, incubators, cooled incubators, thermostatic cabinets and refrigerators has been designed to meet the changing demand of the market. A new front top panel of graphite colour has been introduced to support a brand new LCD graphic display featuring an easy read-out even from a large distance. A user-friendly, intuitive menu with icons on the main screen, illuminated touch buttons and stand-by energy saving mode have greatly facilitated day-to-day operating of the equipment. In addition to the new design, manual air-flap control in the ovens and incubators has been shifted from a dial on the front panel into a fully automatic control that can now be set digitally. The changes allow a software setup of all operating parameters. Moreover, 15 and 32 litre ovens and incubators, previously available in the basic ECO version only, will now be at customers’ disposal in the advanced STD version with all its advantages too. All the products from the Graphite range have been equipped with a USB port for PC software communication. .
Circle no. 241
INTERNATIONAL LABMATE - JANUARY/FEBRUARY 2012
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