scholarly journals Detection of mixed-culture growth in the total biomass data by wavelet transforms

2010 ◽  
Vol 8 (02) ◽  
Author(s):  
H.C. Rosu ◽  
J.S. Murguía ◽  
V. Ibarra-Junquera
Keyword(s):  
Wavelet Transform ◽  
Mixed Culture ◽  
Microbial Growth ◽  
Physical Parameters ◽  
Logarithmic Scale ◽  
Total Biomass ◽  
Growth Processes ◽  
Microbial Species ◽  
Hölder Exponents ◽  
Culture Growth

We have shown elsewhere that the presence of mixed-culture growth of microbial species in fermentation processes can be detected with high accuracy by employing the wavelet transform. This is achieved because the crosses in the different growth processes contributing to the total biomass signal appear as singularities that are very well evidenced through their singularity cones in the wavelet transform; however, we used very simple two-species cases.In this work, we extend the wavelet method to a more complicated illustrative fermentation case of three microbial species for which we employ several wavelets of different number of vanishing moments in order to eliminate possible numerical artifacts. Working in this way allows filtering in a more precise way the numerical values of the Hölder exponents; therefore, we were able to determine the characteristic Hölder exponents for the corresponding crossing singularities of the microbial growth processes and their stability logarithmic scale ranges up to the first decimal in the value of the characteristic exponents. Since calibrating the mixed microbial growth by means of their Hölder exponents could have potential industrial applications, the dependence of the Hölder exponents on the kinetic and physical parameters of the growth models remains as a future experimental task.

scholarly journals Predicting microbial growth in a mixed culture from growth curve data

2019 ◽  
Vol 116 (29) ◽  
pp. 14698-14707 ◽  
Author(s):  
Yoav Ram ◽  
Eynat Dellus-Gur ◽  
Maayan Bibi ◽  
Kedar Karkare ◽  
Uri Obolski ◽  
...  
Keyword(s):  
Mixed Culture ◽  
Microbial Growth ◽  
Growth Curves ◽  
Growth Cycle ◽  
Relative Fitness ◽  
Accurate Estimation ◽  
Environmental Perturbations ◽  
Fitness Consequence ◽  
Culture Growth ◽  
Growth Differences

Determining the fitness of specific microbial genotypes has extensive application in microbial genetics, evolution, and biotechnology. While estimates from growth curves are simple and allow high throughput, they are inaccurate and do not account for interactions between costs and benefits accruing over different parts of a growth cycle. For this reason, pairwise competition experiments are the current “gold standard” for accurate estimation of fitness. However, competition experiments require distinct markers, making them difficult to perform between isolates derived from a common ancestor or between isolates of nonmodel organisms. In addition, competition experiments require that competing strains be grown in the same environment, so they cannot be used to infer the fitness consequence of different environmental perturbations on the same genotype. Finally, competition experiments typically consider only the end-points of a period of competition so that they do not readily provide information on the growth differences that underlie competitive ability. Here, we describe a computational approach for predicting density-dependent microbial growth in a mixed culture utilizing data from monoculture and mixed-culture growth curves. We validate this approach using 2 different experiments withEscherichia coliand demonstrate its application for estimating relative fitness. Our approach provides an effective way to predict growth and infer relative fitness in mixed cultures.

scholarly journals Inferring mixed-culture growth from total biomass data in a wavelet approach

2006 ◽  
Vol 370 (2) ◽  
pp. 777-792 ◽  
Author(s):  
V. Ibarra-Junquera ◽  
P. Escalante-Minakata ◽  
J.S. Murguía ◽  
H.C. Rosu
Keyword(s):  
Mixed Culture ◽  
Total Biomass ◽  
Culture Growth

New experimental findings and biofilm modelling concepts

1995 ◽  
Vol 32 (8) ◽  
pp. 133-140 ◽  
Author(s):  
Oskar Wanner
Keyword(s):  
Mixed Culture ◽  
Molecular Diffusion ◽  
Volume Fraction ◽  
Mathematical Functions ◽  
Phase Volume Fraction ◽  
Microbial Species ◽  
Biofilm Model ◽  
New Findings ◽  
Experimental Side ◽  
Experimental Findings

About ten years ago a mathematical model was presented which describes the spatial distribution and development in time of microbial species in mixed-culture biofilms. The model was based on the continuum approach and was one-dimensional in space. These two concepts still are the basis of practically all biofilm models used today. On the experimental side some remarkable new findings have been made in the past years: transport of dissolved components in the biofilm is not always due to molecular diffusion only, transport of particulate components can not be exclusively related to the net growth rates of the microbial species in the biofilm, the liquid phase volume fraction (porosity) in the biofilm is not a constant, and simultaneous attachment and detachment of cells and particles at the biofilm surface is an essential process. These experimental findings had a significant impact on our notion of biofilm systems and called for the integration of new processes in the original mixed-culture biofilm model. The new processes can reproduce most of the experimental observations, however, they are described by empirical mathematical functions. Their mechanisms and significance for biofilm behavior have not been completely elucidated yet. Thus, the extended mixed-culture biofilm model represents primarily a tool for research on biofilm processes.

Commensalism and Competition in Mixed Cultures of Lactobacillus bulgaricus and Streptococcus thermophilus1

1976 ◽  
Vol 39 (5) ◽  
pp. 337-341 ◽  
Author(s):  
NANCY J. MOON ◽  
G. W. REINBOLD
Keyword(s):  
Mixed Culture ◽  
Rapid Growth ◽  
Acid Production ◽  
Stationary Phases ◽  
Exponential Phase ◽  
Mixed Cultures ◽  
Lactobacillus Bulgaricus ◽  
Single Strain ◽  
Limiting Nutrients ◽  
Culture Growth

Cultures of Streptococcus thermophilis and Lactobacillus bulgaricus produced more acid in mixed than in single strain culture. Growth of S. thermophilus in mixed culture was enhanced during the exponential phase and reached higher numbers in the stationary phase than when grown alone. L. bulgaricus was inhibited in the exponential and stationary phases of growth in mixed culture. L. bulgaricus liberated Seitz-filterable compounds during its growth that stimulated growth and acid production of S. thermophilus. These compounds are believed to be responsible for the commensal response observed in mixed cultures. Because of its rapid growth, S. thermophilus was a better competitor than L. bulgaricus for limiting nutrients in the medium. This resulted in inhibition of the growth of L. bulgaricus. The competitive and commensal response was optimal at 37 C and at a ratio of numbers of lactobacilli to streptococci of 2:1 at inoculation.

scholarly journals An inkling of the relation between the monofractality of temperatures and pressure anomalies

2015 ◽  
Vol 2 (4) ◽  
pp. 1339-1353
Author(s):  
A. Deliège ◽  
S. Nicolay
Keyword(s):  
Wavelet Transform ◽  
Standard Deviation ◽  
Discrete Wavelet Transform ◽  
Air Temperature ◽  
Surface Pressure ◽  
Surface Air Temperature ◽  
Discrete Wavelet ◽  
Long Range Correlations ◽  
Hölder Exponents ◽  
Weather Stations

Abstract. We use the discrete "wavelet transform microscope" to study the monofractal nature of surface air temperature signals of weather stations spread across Europe. This method reveals that the information obtained in this way is richer than previous works studying long range correlations in meteorological stations: the approach presented here allows to bind the Hölder exponents with the standard deviation of surface pressure anomalies, while such a link does not appear with methods previously carried out.

Sign in / Sign up

Export Citation Format

Share Document