Tuesday, September 28, 2010
Saturday, September 18, 2010
Recently Added Rapid Method News Articles
- New Market Report States RMM Usage in the Pharmaceutical and Personal Care Products Sectors Will Double Over The Next Five Years
- Breakthrough Method Cuts E.coli Detection Time in Ground Beef
- MIT Production Start-Up Is on Track and Poised to Significantly Reduce Widespread Food Contamination
- Identification of Clinically Significant Microorganisms
- Bruker Introduces the MALDI Sepsityper™ Kit for Rapid MALDI Biotyper Microbial Identification from Positive Blood Cultures
- Rapid Micro Biosystems Names Julie Sperry to Post of Chief Commercial Officer
New Paper on Rapid Sterility Testing
PDA Technical Report No. 50, Alternative Methods for Mycoplasma Testing
Sunday, September 5, 2010
New paper on viable but not culturable (VBNC) cells and RMMs
Jeanne Moldenhauer has recently published a paper on viability-based RMMs and the types of indicators or markers used in these systems. She writes that some RMMs still rely on the growth of microorganisms, while others are based on viability methods to detect and quantify microorganisms without the need for microbial growth. The use of viability methods has both benefits and challenges, the latter including the potential for obtaining a false positive response (i.e., a viable count from a non-viable cell). A link to Jeanne's paper may be found on our RMM References Page (http://rapidmicromethods.com/files/references.html) under the General Overviews section. The full reference is below:
2010. Moldenhauer, J. Use of a Viability Test Method. Does It Mean What You Think? American Pharmaceutical Review. 13(5): 22-29.
Automating the Micro QC Lab (Part 3)
Michael - Moving from a manual operation to an automated lab is a significant leap. How would you advise companies that are considering using a non-automated rapid method initially, then moving to a more automated option?
Steve – When I speak with companies considering either an automated or non-automated rapid solution, I try to help them explore a few areas. First, I look to uncover where they expect to find the greatest benefit. Certainly, rapid detection provides a clear advantage to the current, manual method in reduced time to results, and not surprisingly, that is the benefit I hear most often. But, as we continue to explore the operation, companies start to realize there are other considerations that need to be addressed. For example, there are risks inherent in any manual process, even a rapid method, such as data entry errors or inconsistency of processes. Could that decrease confidence in the “non-automated” rapid method?
The second area I try to understand is the impact to the operation of the rapid method. Will the “non-automated’ rapid method add steps to the already cumbersome manual process? If there are additional steps, how will that affect the ability for the lab to handle current and future sample workloads? Will there be an increase in resource requirements in the lab, and therefore and increased cost? I often speak with businesses that focus too much on their need for a rapid method, and overlook these types of impacts, missing opportunities for additional benefits through automation.
It is important for the business to understand both the benefits and shortcomings with a non-automated solution. The right answer will be different for each situation, based on how these attributes are weighted. Companies considering both non-automated and automated rapid methods should weigh the importance, benefits and risks to find their optimal solution. And for those technologies that can provide both rapid results and automation, businesses can get the best of both worlds.
In the final part of this series, we talk about automation and validation. Stay tuned.
Friday, September 3, 2010
Next Generation Genome Sequencing
I recently came across an interesting article in the July/August 2010 issue of Australian Life Scientist. It discusses technological advances in the field of genome sequencing that are overcoming cost and speed limitations and opening the door to new applications. Here is an overview of what was discussed:
It took nearly two decades to go from the release of the first semi-automated genome sequencer in the mid-1980s to the launch of Roche’s flagship 454 FLX next generation sequencer in 2005. The 454 is now one of three major players in the next gen market whose impact on the world of genomics cannot be underestimated. Just five years later we are poised to embrace another new wave of sequencing technology. Next gen sequencers, exemplified by Illumina's Solexa Genome Analyzer and the APplied Biosystems SOLiD System, together with 454, are likely to continue to be adapted for myriad use rather than being superceded by the next next gen technology platforms.
The new wave of sequencers, sometimes called the third gen, are creating deal of excitement because they will likely enable scientists to reach the goal of the $US1000 human genome. The third generation of sequencing technology sees single molecules of DNA being sequenced without the need for cloning or PCR amplification and the inherent biases these procedures introduce. There are generally two types of detection methods for single molecule sequencing: those that rely on fluorescence and CCD capture, and those that don’t. Instruments that use the first of these detection methods include the Helicos Heliscope, launched in 2008; Pacific Biosciences single molecule real time sequencing (SMRT) machines, which have been shipped to their first customers; and Life Technologies-VisiGen system, which relies on fluorescence resonance energy transfer (FRET), and Life Technologies expects the first instrument will be placed later this year.
The third generation
The two non-fluorescing technologies operate via quite different methods, with detection systems based on tiny changes in electrical current or pH, thus removing the most expensive components, and associated costs, of sequencing instruments. Both nanopore sequencing, from Oxford Nanopore Technologies (ONT), and Ion Torrent, from Mass Genomics (which was just acquired by Life Technologies), are based on silicon chips. The ONT chip contains hundreds of wells each covered by a lipid bilayer that contains a nanopore – which is a hole around one nanometre in diameter – with each pore an individual electrical channel.
Sequencing is based on exonuclease cleavage of the single DNA strand and detection occurs when the cleaved nucleotide falls through the pore, transiently disrupting the current. The change in current amplitude is unique for each base (A,G,C,T and 5-Methylcytosine - the direct reading of which is unique to nanopore technology). ONT plan to commercialise their nanopore sequencing system by the end of 2010.
Ion Torrent, while also relying on advances in semi-conductor technology, sequences by monitoring DNA synthesis. Single types of nucleotides are sequentially flooded across the chip. Nucleotide incorporation into the new DNA strand results in the release of a H+ ion, which is detected by the pH sensitive dielectric layer. These breadbox–sized benchtop instruments come with an iPod, pre-installed with an application to monitor runs and cycles in real time. The Ion Torrent Personal Genome Machine (PGM) sequencer is just making its way into American research labs now.
Second generation sequencing redux
The third generation upstarts may be on their way, but that doesn’t mean second generation sequencers don’t have more yet to give. Improvements to the technology continue to be made on a number of fronts. They include an increase in the number of wells/reads per plate, superior base-calling algorithms and CCD detection rates and resolution (so the depth of sequencing required can be reduced for the same accuracy), and creation of scaled-down versions of instruments that, cost-wise, will put them in reach of the smaller research laboratories.