Bacterial Normalized Binary Fission Growth Model

2021 ◽  
Author(s):  
John P Keady
Keyword(s):  
Growth Model ◽  
Bacterial Growth ◽  
Bacterial Population ◽  
Size Range ◽  
Control Sample ◽  
Growth Curves ◽  
Growth Cycle ◽  
Binary Fission ◽  
Bacterial Proliferation

Mathematical models have traditionally been used to facilitate the interpretation of bacterial growth curves in order to more accurately understand and identify variations in bacterial proliferation. Here, a binary fission growth model was developed to normalize starting bacterial levels, allowing for the identification of changes in bacterial growth and the separation of a bacterial population as it correlates to size. This normalized binary fission model (NBF) relies on a multi-bin growth mode, where each bin is associated with a size range during a growth cycle. The proposed NBF model allows for a determination of the percentage of treated bacteria eradicated compared to a control sample, either generally across all bacterial binary fission sizes or specific to a size range or bin. Comparisons between the NBF model and experimental observations demonstrates that bacterial growth curves, and the ratio of sample growth to a control, can be used to both determine and normalize initial variations in bacterial size, and quantity, among test samples, as well as identify final nutrient levels and the percentage of bacteria affected by treatment.

scholarly journals Use of the Microbial Growth Curve in Postantibiotic Effect Studies of Legionella pneumophila

2003 ◽  
Vol 47 (3) ◽  
pp. 1081-1087 ◽  
Author(s):  
Raymond P. Smith ◽  
Aldona L. Baltch ◽  
Phyllis B. Michelsen ◽  
William J. Ritz ◽  
Richard Alteri
Keyword(s):  
Minimum Inhibitory Concentration ◽  
Bacterial Growth ◽  
Legionella Pneumophila ◽  
Microbial Growth ◽  
Inhibitory Concentration ◽  
Growth Curves ◽  
Laboratory Medicine ◽  
Postantibiotic Effect ◽  
Antibiotic Concentration

ABSTRACT Using the standard Craig and Gudmundsson method (W. A. Craig and S. Gudmundsson, p. 296-329, in V. Lorian, ed., Antibiotics in Laboratory Medicine, 1996) as a guideline for determination of postantibiotic effects (PAE), we studied a large series of growth curves for two strains of Legionella pneumophila. We found that the intensity of the PAE was best determined by using a statistically fitted line over hours 3 to 9 following antibiotic removal. We further determined the PAE duration by using a series of observations of the assay interval from hours 3 to 24. We determined that inoculum reduction was not necessarily the only predictor of the PAE but that the PAE was subject to the type and dose of the drug used in the study. In addition, there was a variation between strains. Only levofloxacin at five and ten times the minimum inhibitory concentration (MIC) resulted in a PAE duration of 4 to 10 h for both strains of L. pneumophila tested. Ciprofloxacin at five and ten times the MIC and azithromycin at ten times the MIC caused a PAE for one strain only. No PAE could be demonstrated for either strain with erythromycin or doxycycline. Using the presently described method of measuring PAE for L. pneumophila, we were able to detect differences in PAE which were dependent upon the L. pneumophila strain, the antibiotic tested, and the antibiotic concentration. We suggest the use of mathematically fitted curves for comparison of bacterial growth in order to measure PAE for L. pneumophila.

PDO Rotonda’s Red Eggplant Extract: In vitro Determination of Biological Properties and Minerals Bioaccessibility

2020 ◽  
Vol 16 (1) ◽  
pp. 65-74
Author(s):  
Ortensia Ilaria Parisi ◽  
Mariarosa Ruffo ◽  
Fabio Amone ◽  
Rocco Malivindi ◽  
Domenico Gorgoglione ◽  
...  
Keyword(s):  
Control Sample ◽  
Specific Area ◽  
Biological Properties ◽  
Ammonium Molybdate ◽  
Antihypertensive Activity ◽  
Protected Designation Of Origin ◽  
The Family ◽  
Oil Red O Staining

Background: The Rotonda’s Red Eggplant belongs to the family of Solanum aethiopicum and it is cultivated in a specific area of Potenza (Basilicata, South of Italy) including villages of Rotonda, Viggianello, Castelluccio Superiore and Castelluccio Inferiore. The Red Eggplant cultivated in this area has gained the PDO, “Protected Designation of Origin”. Objective: The aim of this research was to evaluate the use of PDO Rotonda’s Red Eggplant extract as a possible nutraceutical supplement. The antioxidant, antihypertensive, hypoglycemic, and hypolipidemic properties were in vitro evaluated. Methods: The antioxidant activity was investigated by evaluating the scavenging properties against 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2-Azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radicals and by performing the Ammonium Molybdate and Folin-Ciocalteu assay. The hypoglycemic and antihypertensive activity was studied by evaluating the α-Amylase, α-Glucosidase and Angiotensin Converting Enzyme, respectively, inhibiting activity. In order to evaluate the hypolipidemic activity, the pancreatic lipase inhibiting property was determined and Oil Red O staining assay was performed. Finally, to evaluate the possible use of this extract as a minerals supplement, Selenium, Potassium and Chrome bioaccessibility was studied. Results: The obtained results underline the good antioxidant, hypoglycemic, antihypertensive and hypolipidemic in vitro properties of the PDO Rotonda’s Red Eggplant extract. Moreover, the obtained data show a higher minerals bioaccessibility and this higher value could be ascribable to the natural phytocomplex of PDO Rotonda’s Red Eggplant, which increases the minerals bioaccessibility if compare it with a control sample. Conclusion: The obtained results show that PDO Rotonda’s Red Eggplant extract, might be used as a possible nutraceutical supplement, along with traditional therapies, both for its biological properties and for its minerals bioaccessibility value.

Determination of a predictive growth model for cultivated African catfish Clarias gariepinus (Burchell, 1882)

2021 ◽  
Author(s):  
Babatunde Olaseni Musa ◽  
Alvaro Hernández‐Flores ◽  
Oludare Akanni Adeogun ◽  
Adekunle Oresegun
Keyword(s):  
Growth Model ◽  
Clarias Gariepinus ◽  
African Catfish

scholarly journals Effect of erythritol and xylitol on Streptococcus pyogenes causing peritonsillar abscesses

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Siiri Kõljalg ◽  
Risto Vaikjärv ◽  
Imbi Smidt ◽  
Tiiu Rööp ◽  
Anirikh Chakrabarti ◽  
...  
Keyword(s):  
Streptococcus Pyogenes ◽  
Bacterial Growth ◽  
Growth Curves ◽  
Culture Collection ◽  
Exponential Phase ◽  
Clinical Isolates ◽  
Growth Inhibitors ◽  
Throat Culture ◽  
Potent Growth

AbstractPolyols are effective against caries-causing streptococci but the effect on oropharynx-derived pyogenic streptococci is not well characterised. We aimed to study the effect of erythritol (ERY) and xylitol (XYL) against Streptococcus pyogenes isolated from peritonsillar abscesses (PTA). We used 31 clinical isolates and 5 throat culture collection strains. Inhibition of bacterial growth by polyols at 2.5%, 5% and 10% concentrations was studied and the results were scored. Amylase levels in PTA pus were compared to polyol effectivity scores (PES). Growth curves of four S. pyogenes isolates were analysed. Our study showed that XYL was more effective than ERY inhibiting 71–97% and 48–84% of isolates, respectively, depending of concentrations. 48% of clinical and all throat strains were inhibited by polyols in all concentrations (PES 3). PES was negative or zero in 26% of the isolates in the presence of ERY and in 19% of XYL. ERY enhanced the growth of S. pyogenes isolated from pus with high amylase levels. Polyols in all concentrations inhibited the growth in exponential phase. In conclusion, ERY and XYL are potent growth inhibitors of S. pyogenes isolated from PTA. Therefore, ERY and XYL may have potential in preventing PTA in the patients with frequent tonsillitis episodes.

Growth of Thiobacillus ferrooxidans on various substrates

1969 ◽  
Vol 15 (1) ◽  
pp. 135-138 ◽  
Author(s):  
C. J. M. McGoran ◽  
D. W. Duncan ◽  
C. C. Walden
Keyword(s):  
Ferrous Iron ◽  
Generation Time ◽  
Bacterial Population ◽  
Thiobacillus Ferrooxidans ◽  
Growth Curves ◽  
Insoluble Material ◽  
Growth System ◽  
Ph Range

When Thiobacillus ferrooxidans was grown on ferrous iron and chalcopyrite (CuFeS2) in excess of 96% of the bacterial population was associated with the insoluble material. When sulfur was the substrate 77% of the bacteria were so associated. This necessitated consideration of the complete growth system to obtain accurate growth curves. By using total bacterial nitrogen as the measure of growth, it was shown that T. ferrooxidans had a minimum generation time of 6.5 to 10 hours on a ferrous iron substrate, 7 to 8 days on a sulfur substrate, and 14 to 17 hours on a chalcopyrite substrate. The pH range for growth was dependent on the substrate used.

Decomposition of Growth Curves into Growth Rate and Acceleration: a Novel Procedure to Monitor Bacterial Growth and the Time-Dependent Effect of Antimicrobials

2021 ◽  
Author(s):  
M. Luisa Navarro-Pérez ◽  
M. Coronada Fernández-Calderón ◽  
Virginia Vadillo-Rodríguez
Keyword(s):  
Growth Rate ◽  
Mathematical Models ◽  
Bacterial Growth ◽  
Time Course ◽  
Antimicrobial Agents ◽  
Numerical Procedure ◽  
Growth Curves ◽  
Predictive Microbiology ◽  
Insight Into ◽  
Over Time

In this paper, a simple numerical procedure is presented to monitor the growth of Streptococcus sanguinis over time in the absence and presence of propolis, a natural antimicrobial. In particular, it is shown that the real-time decomposition of growth curves obtained through optical density measurements into growth rate and acceleration can be a powerful tool to precisely assess a large range of key parameters [ i.e. lag time ( t 0 ), starting growth rate ( γ 0 ), initial acceleration of the growth ( a 0 ), maximum growth rate ( γ max ), maximum acceleration ( a max ) and deceleration ( a min ) of the growth and the total number of cells at the beginning of the saturation phase ( N s )] that can be readily used to fully describe growth over time. Consequently, the procedure presented provides precise data of the time course of the different growth phases and features, which is expected to be relevant, for instance, to thoroughly evaluate the effect of new antimicrobial agents. It further provides insight into predictive microbiology, likely having important implications to assumptions adopted in mathematical models to predict the progress of bacterial growth. Importance: The new and simple numerical procedure presented in this paper to analyze bacterial growth will possibly allow identifying true differences in efficacy among antimicrobial drugs for their applications in human health, food security, and environment, among others. It further provides insight into predictive microbiology, likely helping in the development of proper mathematical models to predict the course of bacterial growth under diverse circumstances.

USE OF MICRO-ALGAE SPIRULINA IN COMBINATION WITH GRAIN ENRICHING ADDITIVES IN THE FORMULATION OF BREAD FROM WHEAT FLOUR

2020 ◽  
Author(s):  
А.А. ГРЯЗНОВ ◽  
Ю.А. ЛЕТЯГО ◽  
О.А. ГРЯЗНОВА ◽  
Р.И. БЕЛКИНА
Keyword(s):  
Wheat Flour ◽  
Control Sample ◽  
High Volume ◽  
Barley Grain ◽  
Wheat Bread ◽  
Chemical Indicators ◽  
Physico Chemical ◽  
State Commission ◽  
Three Samples

Исследовано влияние добавки микроводоросли спирулины в рецептуру хлеба из пшеничной муки, обогащенного обойной мукой из зерна ячменя сортов Гранал 32 и Нудум 95 и тритикале сорта Цекад 90, на показатели его качества. Размолотую до порошкообразного состояния спирулину в количестве 0,5 к массе муки вносили при замесе теста в три опытных образца: пшеничный хлеб, хлеб Гранал и Ясень , рецептуры которых были разработаны ранее. В качестве контрольного образца был хлеб из пшеничной муки высшего сорта без добавок. Лабораторную выпечку образцов хлеба проводили в соответствии с методикой госкомиссии по сортоиспытанию на лабораторном хлебопекарном оборудовании. В результате определения органолептических и физико-химических показателей качества готовой продукции установлено, что добавка спирулины к пшеничной муке повышает пористость мякиша хлеба и увеличивает его объем до 546 см3, что на 18 см3 больше, чем в контрольном образце. Достаточно высокий объем 494 см3 имел образец хлеба, в рецептуру которого входит ячменная мука с добавлением спирулины. Внесение спирулины в рецептуру существенно не повлияло на показатели влажности (4346) и кислотности хлеба, которые в опытных образцах соответствуют нормативам ГОСТ 2698786 на хлеб из пшеничной муки. Самую высокую общую оценку 4,2 балла по пятибалльной шкале получил образец хлеба с добавлением к пшеничной муке порошка спирулины. The effect of the addition of spirulina microalgae in the formulation of bread from wheat flour enriched with wholemeal flour from barley grain varieties Granal 32 and Nudum 95 and triticale varieties Tsekad 90, on the indicators of its quality has been studied. Spirulina ground to a powdered state in an amount of 0,5 by weight of flour was introduced when kneading the dough into the formulations of three samples: wheat bread, bread Granal and Yasen , the formulations of which were developed earlier. Bread from wheat flour of the highest grade without additives was as a control sample. Laboratory baking of bread samples was carried out in accordance with the methodology of the state Commission for variety testing on laboratory baking equipment. As a result of the determination of organoleptic and physico-chemical indicators of the quality of the finished product, it was found that the addition of spirulina to wheat flour increases the porosity of the bread crumb and increases its volume to 546 cm3, which is 18 cm3 more than in the control sample. A sample of bread, the formulation of which includes barley flour with the addition of spirulina, had a sufficiently high volume 494 cm3. Adding spirulina to the formulation did not significantly affect the moisture content (4346) and acidity of bread, which in the prototypes correspond to the standards of GOST 2698786 for bread made of wheat flour. A sample of bread with spirulina powder added to wheat flour had the highest overall score 4б2 points on a five-point scale.

Investigation of Radiant Superheater Crossover Pipe Weld Cracking at Big Cajun II Station

2002 ◽  
Author(s):  
James P. King ◽  
Robert D. Hendrix
Keyword(s):  
Growth Curves ◽  
Performance Testing ◽  
Circumferential Welds ◽  
Root Cause ◽  
Ultrasonic Time ◽  
History Of ◽  
The Many ◽  
Stress Fatigue ◽  
Ultrasonic Shear

This paper describes the many features of a detailed investigation into the determination of a root cause for internal cracking found in the circumferential welds of radiant superheater crossover piping lines, in the Units No. 1 and 2 boilers at Big Cajun II Station in New Roads, Louisiana. The history of inside diameter, circumferential cracks dates back to 1992. The cracking had been recorded during several outages for both units. It was discovered by use of ultrasonic shear wave testing, and verified by ultrasonic time of flight diffraction methods. During each of the ensuing unit outages, the crack depths were recorded and mapped. Repairs were undertaken by machining out the complete girth weld followed by re-welding. During the interim years cracking did re-occur at many of the weld locations. In 2000, a detailed investigation into the cause of the cracking was initiated, which resulted in recommendations for resolving the ongoing problem. This detailed study included; nondestructive testing and metallurgy of removed metal samples, boiler performance testing and analysis and stress, fatigue and fracture mechanics evaluations. The detailed background, applications and results of the many and varied testing and analytical tasks are fully described herein. The main conclusion to the root cause of the cracking is identified as fatigue caused by the combined effects of thermal and pressure cycles. Recommendations are given which address the actions needed to limit or prevent re-occurrence of the cracking, including revised boiler operating procedures. In addition, a series of fatigue crack growth curves is presented, as a monitoring toot for evaluating existing cracks in the welds.

Growth of the saucer scallop, Amusium japonicum balloti Habe, in central eastern Queensland

1981 ◽  
Vol 32 (4) ◽  
pp. 657 ◽  
Author(s):  
MJ Williams ◽  
MCL Dredge
Keyword(s):  
Growth Model ◽  
Larval Stage ◽  
Size Range ◽  
Von Bertalanffy ◽  
Commercial Fishery ◽  
Long Distance ◽  
Von Bertalanffy Growth Model ◽  
Central Eastern

Tag-recapture data were used to determine growth and movement of A. japonicum balloti. The von Bertalanffy growth model was found to be suitable for describing growth in the latter half of the size range for A. japonicum balloti, and estimated S∞ of scallops varied with year and area. A. japonicum balloti grows rapidly, being recruited to the commercial fishery at about 6 months of age in some cases. Recapture data indicated that A. japonicum balloti does not undergo long-distance displacements in its post-larval stage.

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