FRACTAL GROWTH OF BACTERIAL COLONIES

Fractals ◽  
1995 ◽  
Vol 03 (04) ◽  
pp. 869-877 ◽  
Author(s):  
FEREYDOON FAMILY
Keyword(s):  
Experimental Data ◽  
Escherichia Coli ◽  
Bacillus Subtilis ◽  
Power Law ◽  
Bacterial Growth ◽  
Phenomenological Approach ◽  
Nutrient Concentrations ◽  
Statistical Fluctuations ◽  
The Mean ◽  
Different Strains

The dynamics of the growth of three different strains of bacteria, ATCC 25589, Bacillus subtilis and Escherichia coli, was studied under different conditions of low as well as rich nutrient concentrations. We find that within the statistical fluctuations in the experimental data, the mean radius of the bacterial colonies grow with a power of time and the exponent characterizing this power law growth has an anomalous value. We present and discuss a simple phenomenological approach for explaining the existence of anomalous power-law exponents in bacterial growth. This approach may be useful in determining the key mechanisms which control the growth and morphology of bacterial colonies.

Bacterial growth in space flight: logistic growth curve parameters for Escherichia coli and Bacillus subtilis

1999 ◽  
Vol 51 (2) ◽  
pp. 229-234 ◽  
Author(s):  
M. A. Kacena ◽  
G. A. Merrell ◽  
B. Manfredi ◽  
E. E. Smith ◽  
D. M. Klaus ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Bacillus Subtilis ◽  
Bacterial Growth ◽  
Growth Curve ◽  
Space Flight ◽  
Logistic Growth

Equilibrium similarity solution of the turbulent transport equation along the centreline of a round jet

2015 ◽  
Vol 772 ◽  
pp. 740-755 ◽  
Author(s):  
H. Sadeghi ◽  
P. Lavoie ◽  
A. Pollard
Keyword(s):  
Experimental Data ◽  
Kinetic Energy ◽  
Structure Function ◽  
Transport Equation ◽  
Power Law ◽  
Turbulent Jet ◽  
Order Structure ◽  
Current Analysis ◽  
Power Law Decay ◽  
The Mean

A novel similarity-based form is derived of the transport equation for the second-order velocity structure function of$\langle ({\it\delta}q)^{2}\rangle$along the centreline of a round turbulent jet using an equilibrium similarity analysis. This self-similar equation has the advantage of requiring less extensive measurements to calculate the inhomogeneous (decay and production) terms of the transport equation. It is suggested that the normalised third-order structure function can be uniquely determined when the normalised second-order structure function, the power-law exponent of$\langle q^{2}\rangle$and the decay rate constants of$\langle u^{2}\rangle$and$\langle v^{2}\rangle$are available. In addition, the current analysis demonstrates that the assumption of similarity, combined with an inverse relation between the mean velocity$U$and the streamwise distance$x-x_{0}$from the virtual origin (i.e. $U\propto (x-x_{0})^{-1}$), is sufficient to predict a power-law decay for the turbulence kinetic energy ($\langle q^{2}\rangle \propto (x-x_{0})^{m}$), rather than requiring a power-law decay ($m=-2$) as an additionalad hocassumption. On the basis of the current analysis, it is suggested that the mean kinetic energy dissipation rate,$\langle {\it\epsilon}\rangle$, varies as$(x-x_{0})^{m-2}$. These theoretical results are tested against new experimental data obtained along the centreline of a round turbulent jet as well as previously published data on round jets for$11\,000\leqslant \mathit{Re}_{D}\leqslant 184\,000$over the range$10\leqslant x/D\leqslant 90$. For the present experiments,$\langle q^{2}\rangle$exhibits power-law behaviour with$m=-1.83$. The validity of this solution is confirmed using other experimental data where$\langle q^{2}\rangle$follows a power law with$-1.89\leqslant m\leqslant -1.78$. The present similarity form of the transport equation for$\langle ({\it\delta}q)^{2}\rangle$is also shown to be closely satisfied by the experimental data.

scholarly journals Quantitative examination of five stochastic cell-cycle and cell-size control models for Escherichia coli and Bacillus subtilis

2021 ◽  
Author(s):  
Guillaume Le Treut ◽  
Fangwei Si ◽  
Dongyang Li ◽  
Suckjoon Jun
Keyword(s):  
Experimental Data ◽  
Escherichia Coli ◽  
Cell Cycle ◽  
Bacillus Subtilis ◽  
Cell Size ◽  
Size Control ◽  
Statistical Analysis Method ◽  
Quantitative Examination ◽  
Cell Size Control ◽  
Bacterial Cell Cycle

We examine five quantitative models of the cell-cycle and cell-size control in Escherichia coli and Bacillus subtilis that have been proposed over the last decade to explain single-cell experimental data generated with high-throughput methods. After presenting the statistical properties of these models, we test their predictions against experimental data. Based on simple calculations of the defining correlations in each model, we first dismiss the stochastic Helmstetter-Cooper model and the Initiation Adder model, and show that both the Replication Double Adder and the Independent Double Adder model are more consistent with the data than the other models. We then apply a recently proposed statistical analysis method and obtain that the Independent Double Adder model is the most likely model of the cell cycle. By showing that the Replication Double Adder model is fundamentally inconsistent with size convergence by the adder principle, we conclude that the Independent Double Adder model is most consistent with the data and the biology of bacterial cell-cycle and cell-size control. Mechanistically, the Independent Adder Model is equivalent to two biological principles: (i) balanced biosynthesis of the cell-cycle proteins, and (ii) their accumulation to a respective threshold number to trigger initiation and division.

Bacterial Growth and Vitamin Content of Milk1

1976 ◽  
Vol 39 (5) ◽  
pp. 325-327 ◽  
Author(s):  
L. GLASS ◽  
T. I. HEDRICK
Keyword(s):  
Bacillus Subtilis ◽  
Vitamin A ◽  
Bacterial Growth ◽  
Average Concentration ◽  
Retail Stores ◽  
Vitamin Content ◽  
Streptococcus Lactis ◽  
Whole Milk ◽  
The Mean

Five brands of whole milk from retail stores were analyzed for quantitative vitamin changes when the samples had developed off flavor in storage at 10 C. Vitamins A, B6, and niacin decreased by a small but significant amount. Average concentration of thiamine, riboflavin, and B12 were not changed during bacterial growth. Cultures for Dagano cheese and yogurt and two strains of Streptococcus lactis decreased the contents of Vitamin A, riboflavin, and B12 during growth. The averages for thiamine and B6 content were not significantly changed. Niacin content was decreased by growth of each of the four cultures. Three strains of Bacillus subtilis and six other species of bacteria that caused off flavor in milk during growth produced no significant changes in contents of Vitamins A, B6, B12, and riboflavin. The mean contents of thiamine and niacin were decreased, but two species did not cause a decrease in niacin.

scholarly journals Quantitative Examination of Five Stochastic Cell-Cycle and Cell-Size Control Models for Escherichia coli and Bacillus subtilis

2021 ◽  
Vol 12 ◽  
Author(s):  
Guillaume Le Treut ◽  
Fangwei Si ◽  
Dongyang Li ◽  
Suckjoon Jun
Keyword(s):  
Experimental Data ◽  
Escherichia Coli ◽  
Cell Cycle ◽  
Bacillus Subtilis ◽  
Cell Size ◽  
Size Control ◽  
Statistical Analysis Method ◽  
Quantitative Examination ◽  
Cell Size Control ◽  
Bacterial Cell Cycle

We examine five quantitative models of the cell-cycle and cell-size control in Escherichia coli and Bacillus subtilis that have been proposed over the last decade to explain single-cell experimental data generated with high-throughput methods. After presenting the statistical properties of these models, we test their predictions against experimental data. Based on simple calculations of the defining correlations in each model, we first dismiss the stochastic Helmstetter-Cooper model and the Initiation Adder model, and show that both the Replication Double Adder (RDA) and the Independent Double Adder (IDA) model are more consistent with the data than the other models. We then apply a recently proposed statistical analysis method and obtain that the IDA model is the most likely model of the cell cycle. By showing that the RDA model is fundamentally inconsistent with size convergence by the adder principle, we conclude that the IDA model is most consistent with the data and the biology of bacterial cell-cycle and cell-size control. Mechanistically, the Independent Adder Model is equivalent to two biological principles: (i) balanced biosynthesis of the cell-cycle proteins, and (ii) their accumulation to a respective threshold number to trigger initiation and division.

Bacteristatic activity of phenanthrolines against Escherichia coli and Bacillus subtilis

1985 ◽  
Vol 31 (4) ◽  
pp. 367-370 ◽  
Author(s):  
Patrick Sharrock
Keyword(s):  
Escherichia Coli ◽  
Bacillus Subtilis ◽  
Copper Ions ◽  
Lethal Dose ◽  
Toxic Substance ◽  
Antibacterial Action ◽  
E Coli ◽  
Viable Cells ◽  
The Mean

Using optical turbidimetry to measure the growth of Escherichia coli and Bacillus subtilis, we determined the mean lethal dose (LD50) values for various phenanthrolines. The dimethyl-substituted compounds are found to be more toxic to bacteria, with doses near 5 μg/mL reducing the number of viable cells by 50% over a 24-h period. 2,9-Dimethyl phenanthroline is the most potent compound against B. subtilis, being six times more effective than against E. coli. Bipyridine is the least toxic substance and is twice as effective against E. coli as it is against B. subtilis. Evidence is presented to show copper ions enhance the antibacterial action of phenanthrolines and may be required for activity.

scholarly journals Dependence of the cut-off parameters for the cluster reconstruction on incident momenta

2018 ◽  
pp. 22-30
Author(s):  
Shinebayar Janchiv ◽  
Togoo Ravdandorj ◽  
Tursukh Amgalan ◽  
Otgonsuren Dalkhajav ◽  
Munkhjargal Lkhagvadorj
Keyword(s):  
Experimental Data ◽  
Power Law ◽  
Nuclear Emulsion ◽  
Mean Value ◽  
Incident Momentum ◽  
Cluster Number ◽  
Mean Values ◽  
Cone Algorithm ◽  
The Mean ◽  
Number Of Particles

In this work, firstly, we have determined the multiplicities of protons that are involved from projectiles to interactions, and secondly, the mean incident momentum using experimental data on the collisions of proton, helium, oxygen, silicon, and sulfur with the nuclear emulsion at 4.5A GeV/c. We have studied the dependences of clot numbers, number of particles in the clot, rapidity, and the mean azimuthal value on the variable dij, and the dependence of the cluster number on the mean value of the variable dij. Using the “Cone” algorithm for the clustering, we have precisely identified that the cut-off parameter to compose the clusters consisted of s and f tracks produced in (p, He, C, O, Si, S) + Em collisions decreases by the power law with mean values of incident momentum.

Antagonistic activity of Bacillus subtilis strains isolated from various sources

2018 ◽  
Vol 8 (2) ◽  
pp. 354-364
Author(s):  
A. N. Irkitova ◽  
A. V. Grebenshchikova ◽  
A. V. Matsyura
Keyword(s):  
Escherichia Coli ◽  
Bacillus Subtilis ◽  
Wild Strain ◽  
Fish Farming ◽  
Antagonistic Activity ◽  
Antagonistic Effect ◽  
E Coli ◽  
Long Period ◽  
Test Culture ◽  
Agar Media

<p>An important link in solving the problem of healthy food is the intensification of the livestock, poultry and fish farming, which is possible only in the adoption and rigorous implementation of the concept of rational feeding of animals. In the implementation of this concept required is the application of probiotic preparations. Currently, there is an increased interest in spore probiotics. In many ways, this can be explained by the fact that they use no vegetative forms of the bacilli and their spores. This property provides spore probiotics a number of advantages: they are not whimsical, easily could be selected, cultivated, and dried. Moreover, they are resistant to various factors and could remain viable during a long period. One of the most famous spore microorganisms, which are widely used in agriculture, is <em>Bacillus subtilis</em>. Among the requirements imposed to probiotic microorganisms is mandatory – antagonistic activity to pathogenic and conditional-pathogenic microflora. The article presents the results of the analysis of antagonistic activity of collection strains of <em>B. subtilis</em>, and strains isolated from commercial preparations. We studied the antagonistic activity on agar and liquid nutrient medias to trigger different antagonism mechanisms of <em>B. subtilis</em>. On agar media, we applied three diffusion methods: perpendicular bands, agar blocks, agar wells. We also applied the method of co-incubating the test culture (<em>Escherichia coli</em>) and the antagonist (or its supernatant) in the nutrient broth. Our results demonstrated that all our explored strains of <em>B. subtilis</em> have antimicrobial activity against a wild strain of <em>E. coli</em>, but to varying degrees. We identified strains of <em>B. subtilis</em> with the highest antagonistic effect that can be recommended for inclusion in microbial preparations for agriculture.</p><p><em><br /></em><em></em></p>

The Study of Bacillus Subtils Antimicrobial Activity on Some of the Pathological Isolates

2019 ◽  
Vol 9 (02) ◽  
Author(s):  
Hussein A Kadhum ◽  
Thualfakar H Hasan2
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Antimicrobial Activity ◽  
Bacillus Subtilis ◽  
Bacterial Growth ◽  
Broad Spectrum ◽  
Inhibitory Activity ◽  
Bacterial Pathogens ◽  
Inhibitory Ability ◽  
Selection Of

The study involved the selection of two isolates from Bacillus subtilis to investigate their inhibitory activity against some bacterial pathogens. B sub-bacteria were found to have a broad spectrum against test bacteria such as Staphylococcus aureus and Pseudomonas aeruginosa. They were about 23-30 mm and less against Klebsiella sp. The sensitivity of some antibodies was tested on the test samples. The results showed that the inhibitory ability of bacterial growth in the test samples using B. subtilis extract was more effective than the antibiotics used.

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