Serial Dilution

SciVee ◽  
2010 ◽  
Keyword(s):  
Serial Dilution

scholarly journals STUDIES ON THE BACTERIOPHAGE OF D'HERELLE

1925 ◽  
Vol 42 (4) ◽  
pp. 483-497 ◽  
Author(s):  
Jacques J. Bronfenbrenner ◽  
Charles Korb
Keyword(s):  
Quantitative Evaluation ◽  
Bacterial Species ◽  
Relative Concentration ◽  
Serial Dilution ◽  
The Other ◽  
Resistant Bacteria ◽  
Dilution Method ◽  
High Concentration ◽  
Average Size ◽  
Broth Dilution

The experiments reported above confirm the fact that lytic principle is distributed in active solution in a state of indivisible units. This permits its quantitative evaluation by serial dilution, as well as by plating on agar. The latter method, however, often gives readings considerably lower than those obtained by the broth dilution method of titration. By varying the concentration of agar it has been possible to show that the discrepancy is due to adsorption of the lytic agent on agar. When the concentration of the latter is increased from 0.3 per cent to 2.5 per cent the number of plaques of lysis is reduced more than 100 times. At the same time the average size of the plaques also decreases approximately to one-tenth of the original. The size, as well as the number of plaques, has been found to depend also on the condition of the culture employed in titration. Thus, when the culture exposed to the action of lytic agent is composed of young susceptible bacteria, the greater the concentration of bacteria, the smaller the plaques. When the culture is composed partly of young and partly of old susceptible bacteria, both the size and the number of the plaques are diminished with the increase in the relative concentration of old bacteria. On the other hand, presence in the culture of resistant bacteria does not affect either the size or the number of the plaques so long as the relative concentration of susceptible bacteria in the culture is sufficient to allow formation of them. The plaques appearing in the presence of a high concentration of resistant variants in the culture are relatively indistinct owing to overgrowth. Under carefully controlled conditions the size of plaques is found to be determined by the character of the lytic filtrate. Thus in the case of lytic agents which act upon more than one bacterial species the size of the plaques remains constant, irrespective of the bacterial substratum used for the production of the active filtrate.

Four-parameter paired response curve for serial dilution assays

2021 ◽  
pp. 1-16
Author(s):  
Youyi Fong ◽  
Sallie R. Permar ◽  
Georgia D. Tomaras
Keyword(s):  
Response Curve ◽  
Serial Dilution

scholarly journals ANTIBIOTICS RESISTANCE OF CORYNEBACTERIUM NON DIPHTHERIAE STRAINS

2017 ◽  
pp. 3-8
Author(s):  
G. G. Kharseeva ◽  
N. A. Voronina ◽  
T. D. Gasretova ◽  
O. I. Sylka ◽  
S. Yu. Tyukavkina
Keyword(s):  
Serial Dilution ◽  
Urogenital Tract ◽  
Antibiotics Resistance ◽  
Dilution Method ◽  
Frequency Of Occurrence ◽  
Serial Dilution Method ◽  
Resistant Strains

Aim. Study the frequency of occurrence of antibiotics resistant strains of various species of Corynebacterium non diptheriae. Materials and methods. C.pseudodiphtheriticum, C.pseudotuberculosis, C.xerosis, C.amycolatum, C.striatum, C.ulcerans strains isolated from patients with pathologies of respiratory and urogenital tract, as well as individuals taking prophylaxis examination were used. Sensitivity to antibacterial preparations was determined by the serial dilution method. Results. The highest number of Corynebacterium non diptheriae strains displayed resistance to benzylpenicillin (54.8%) and lincomycin (50.7%), and lowest - to cefotaxime, cefazolin (6.8%) and vancomycin (13.7%). The highest number of antibiotics resistant strains were detected among members of C.pseudotuberculosis {100%), C.xerosis (96.0%) and C. pseudodiphtheriticum (81.0%) species. Polyresistant strains were detected most frequently among C.xerosis, C.amycolatum and C.striatum species. Strains of Corynebacterium non diptheriae most frequently displayed resistance to 1 or 2 antibacterial preparations (24.7%), less frequently - to 3 (20.5%), 4 (13.7%), 5 (4.1%) and 6 (1.4%) preparations. Conclusion. The amount of antibiotics resistant strains of Corynebacterium non diptheriae is large (89.0%) and non-similar in various species.

Integrated Serial Dilution on a Microchip for Immunoassay Sample Treatment and Flow Injection Analysis

1998 ◽  
pp. 157-160 ◽  
Author(s):  
Siew Bang Cheng ◽  
Cameron D. Skinner ◽  
D. Jed Harrison
Keyword(s):  
Flow Injection ◽  
Flow Injection Analysis ◽  
Serial Dilution ◽  
Sample Treatment

Preparing Yeast Suspension Through Serial Dilution for Enumeration

2021 ◽  
pp. 77-81
Author(s):  
Cíntia Lacerda Ramos ◽  
Karina Teixeira Magalhães-Guedes
Keyword(s):  
Serial Dilution ◽  
Yeast Suspension

scholarly journals Pooling RT-qPCR testing for SARS-CoV-2 in 1000 individuals of healthy and infection-suspected patients

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Yosuke Hirotsu ◽  
Makoto Maejima ◽  
Masahiro Shibusawa ◽  
Yuki Nagakubo ◽  
Kazuhiro Hosaka ◽  
...  
Keyword(s):  
Healthcare Workers ◽  
Limit Of Detection ◽  
Serial Dilution ◽  
Clinical Settings ◽  
Synthetic Dna ◽  
Pooling Strategy ◽  
Status Information ◽  
A Prospective Study ◽  
Respiratory Coronavirus ◽  
Pooled Samples

Abstract Severe acute respiratory coronavirus 2 (SARS-CoV-2) testing reagents are expected to become scarce worldwide. However, little is known regarding whether pooling of samples accurately detects SARS-CoV-2. To validate the feasibility of pooling samples, serial dilution analysis and spike-in experiments were conducted using synthetic DNA and nucleic acids extracted from SARS-CoV-2-positive and -negative patients. Furthermore, we studied 1000 individuals, 667 of whom were “healthy” individuals (195 healthcare workers and 472 hospitalized patients with disorders other than COVID-19 infection), and 333 infection-suspected patients with cough and fever. Serial dilution analysis showed a limit of detection of around 10–100 viral genome copies according to the protocol of the National Institute of Infectious Diseases, Japan. Spike-in experiments demonstrated that RT-qPCR detected positive signals in pooled samples with SARS-CoV-2-negative and -positive patients at 5-, 10-, 20-fold dilutions. By screening with this pooling strategy, by the end of April 2020 there were 12 SARS-CoV-2-positive patients in 333 infection-suspected patients (3.6%) and zero in 667 “healthy” controls. We obtained these results with a total of 538 runs using the pooling strategy, compared with 1000 standard runs. In a prospective study, we successfully detected SARS-CoV-2 using 10- to 20-fold diluted samples of nasopharyngeal swabs from eighteen COVID-19 patients with wide ranges of viral load. Pooling sample is feasible for conserving test reagents and detecting SARS-CoV-2 in clinical settings. This strategy will help us to research the prevalence infected individuals and provide infected-status information to prevent the spread of the virus and nosocomial transmission.

Measurements of Endpoint Titers Based on the Fluorescence Intensity Trend in Anti-Nuclear Antibody Testing

2019 ◽  
Vol 51 (5) ◽  
pp. 469-477 ◽  
Author(s):  
Dong I L Won
Keyword(s):  
Fluorescence Intensity ◽  
Error Rate ◽  
Antinuclear Antibody ◽  
Regression Line ◽  
Cost Effective ◽  
Serial Dilution ◽  
Automated Systems ◽  
Antibody Testing ◽  
Single Well ◽  
Line Slope

Abstract Background Automated systems for antinuclear antibody (ANA) testing provide endpoint titers that are predicted based on the fluorescence intensity (FI) value at a screening dilution (single-well titration [SWT]) showing frequent titration errors (more than plus or minus 1 dilution). Methods Line slope titration (LST) was based on the trend of FI values on dilutions. Three dilutions per specimen were prepared considering a patient’s previous titer or FI at the screening dilution. On the XY plot, with the reciprocal of dilution as the X-axis and FI value as the Y-axis, a fitted line was drawn to obtain the endpoint titers. Results The titration error rate (no. of errors/total no.) of LST using a regression line was lower than that of SWT (31/710 [4.4%] and 152/674 [22.6%], respectively; P < .000000001), with serial dilution as a reference. When comparing a regression line using 3 dilution points with a line using 2 dilution points, the error rate of the former was not significantly different from that of the latter (31/710 [4.4%] and 31/746 [4.2%], respectively; P = .842). Conclusions This LST method is useful as an accurate, cost-effective, and rapid approach to measure endpoint titers in routine ANA testing.

scholarly journals Evolution of Microbial Growth Traits Under Serial Dilution

Genetics ◽  
2020 ◽  
Vol 215 (3) ◽  
pp. 767-777
Author(s):  
Jie Lin ◽  
Michael Manhart ◽  
Ariel Amir
Keyword(s):  
Growth Rate ◽  
Growth Traits ◽  
Lag Time ◽  
Microbial Evolution ◽  
Serial Dilution ◽  
Direct Selection ◽  
Dilution Factor ◽  
Beneficial Mutation ◽  
Experimental Parameters ◽  
Selection Of

Selection of mutants in a microbial population depends on multiple cellular traits. In serial-dilution evolution experiments, three key traits are the lag time when transitioning from starvation to growth, the exponential growth rate, and the yield (number of cells per unit resource). Here, we investigate how these traits evolve in laboratory evolution experiments using a minimal model of population dynamics, where the only interaction between cells is competition for a single limiting resource. We find that the fixation probability of a beneficial mutation depends on a linear combination of its growth rate and lag time relative to its immediate ancestor, even under clonal interference. The relative selective pressure on growth rate and lag time is set by the dilution factor; a larger dilution factor favors the adaptation of growth rate over the adaptation of lag time. The model shows that yield, however, is under no direct selection. We also show how the adaptation speeds of growth and lag depend on experimental parameters and the underlying supply of mutations. Finally, we investigate the evolution of covariation between these traits across populations, which reveals that the population growth rate and lag time can evolve a nonzero correlation even if mutations have uncorrelated effects on the two traits. Altogether these results provide useful guidance to future experiments on microbial evolution.

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