For liquid samples 10 0 -10 5 dilutions, and for colloidal suspensions and solid samples (10% w/v), 10 1 -10 6 dilutions were used. For pure cultures, serial dilutions were prepared from 0.1 OD (10 0 ) stock and 20 μl aliquots of six dilutions (10 1 -10 6 ) were applied as 10-15 micro-drops in six sectors over agar-gelled medium in 9-cm plates. We propose a simple technique for bacterial and yeast cfu estimations from diverse samples with no prior idea of viable counts, designated as single plate- serial dilution spotting (SP-SDS) with the prime recommendation of sample anchoring (10 0 stocks).
Thomas, Pious Sekhar, Aparna C Upreti, Reshmi Mujawar, Mohammad M Pasha, Sadiq S Optimization of single plate- serial dilution spotting (SP-SDS) with sample anchoring as an assured method for bacterial and yeast cfu enumeration and single colony isolation from diverse samples. Quantitative and qualitative assessments were conducted during the semester to determine the value of this approach for… The 5E model of inquiry-based learning was incorporated into a sophomore-level microbiology laboratory to increase student understanding of serial dilutions, a concept that is often difficult for most students to comprehend. Implementing Inquiry-Based Learning in Teaching Serial Dilutions This exercise helps students gain skill at performing dilutions without using reagents, bacterial cultures, or viral cultures, while being able to visualize the process. In this short dry lab exercise, students perform serial dilutions using seed beads. Serial dilution is often a difficult concept for students to understand. Keler, Cynthia Balutis, Tabitha Bergen, Kim Laudenslager, Bryanna Rubino, Deanna PMID:17073422ĮRIC Educational Resources Information Center This microfluidic circuit is generally applicable for integrating automated serial dilution and sample preparation in almost any microfluidic architecture. Mixing is precisely controlled by changing the cyclic pumping rate, with a minimum mixing time of 22 s. Each dilution process, which is comprised of a diluent flush cycle followed by a mixing cycle, is carried out with no pipeting, and a sample volume of 400 nL is sufficient for conducting an arbitrary number of serial dilutions. By varying the valve placement in the circuit, carryover fractions from 0.04 to 0.2 were obtained. The 400-nL serial dilution circuit contains five integrated membrane valves: three two-way valves arranged in a loop to drive cyclic mixing of the diluent and carryover, and two bus valves to control fluidic access to the circuit through input and output channels. To solve this problem, a microfluidic circuit has been fabricated in a three-layer glass-PDMS-glass device. In vitro evolution of RNA molecules requires a method for executing many consecutive serial dilutions. The method maintains this accuracy even in the presence of dilution errors of up to 10% (for both the aliquot and diluent volumes), microbial counts between 10(4) and 10(12) colony-forming units, dilution ratios from 2 to 100, and plate size to colony size ratios between 6.25 to 200. The proposed approach shows relative accuracy well within Â☐.1log10 from data produced by computer simulations. The required inputs are the plate size, the microbial colony size, and the serial dilution factors. The estimate of the optimal count given by our method can be used to narrow the search for the best (optimal) dilution plate and saves time. Our method selects the best agar plate with which to estimate the microbial counts, and takes into account the colony size and plate area that both contribute to the likelihood of miscounting the number of colonies on a plate. The number (concentration) of viable microbial organisms is estimated from a single dilution plate (assay) without a need for replicate plates. A simple method is presented to estimate the microbial counts obtained with the serial dilution technique for microorganisms that can grow on bacteriological media and develop into a colony. Titration of microorganisms in infectious or environmental samples is a corner stone of quantitative microbiology. Estimation method for serial dilution experiments.
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