Validation of a model for predicting the combined effect of three environmental factors on both exponential and lag phases of bacterial growth: temperature, salt concentration and pH

1995 ◽  
Vol 28 (3) ◽  
pp. 233-237 ◽  
Author(s):  
K.R. Davey ◽  
B.J. Daughtry
Keyword(s):  
Environmental Factors ◽  
Bacterial Growth ◽  
Salt Concentration ◽  
Growth Temperature ◽  
Combined Effect ◽  
Lag Phases

scholarly journals Optimasi Suhu Dan Ph Pertumbuhan Lactococus Lactic Isolat Ikan Kerapu

2016 ◽  
Vol 19 (2) ◽  
pp. 166
Author(s):  
Subagiyo Subagiyo ◽  
Ria Azizazh Tri Nuraeni ◽  
Wilis Ari Setyati ◽  
Adi Santoso
Keyword(s):  
Environmental Factors ◽  
Lactococcus Lactis ◽  
Optical Density ◽  
Bacterial Growth ◽  
Growth Temperature ◽  
Rapid Growth ◽  
Microbial Growth ◽  
Ph Value ◽  
Cell Production ◽  
Initial Ph

Temperature and pH is one of the environmental factors that influence microbial growth, so it needs to be optimized in order to obtain optimum values for cell production. The experiments were performed using the medium of   ROGOSA and Sharpe (MRS). The pH value is set with the addition of 1 N NaOH and 1N HCl to obtain a pH value of 4, 5, 6, 7, and 8. Optimization of temperature performed by incubation at 25, 30, 35 and 40 oC. Bacterial growth was measured by changes in optical density at 600 nm wave-lengh. The results showed that the initial pH of 7 is the initial pH value which produces the most rapid growth, while the initial pH 4 provides the slowest growth. Temperature that produces the most rapid growth is 30 and 35 ° C while the temperature 40oC produce the slowest growth.  Keywords : Lactococcus lactis, temperature, pH, growthSuhu dan pH merupakan salah satu faktor lingkungan yang berpengaruh terhadap pertumbuhan mikrobia, sehingga perlu untuk dilakukan optimasi guna mendapatkan nilai-nilai yang optimum untuk produksi sel. Percobaan dilakukan menggunakan medium deMan, Rogosa and Sharpe (MRS). Nilai pH  diatur dengan penambahan NaOH 1 N dan HCL 1N hingga diperoleh nilai pH 4, 5, 6, 7, dan 8.. Optimasi suhu dilakukan dengan inkubasi pada suhu 25, 30, 35 dan 40 oC . Pertumbuhan bakteri diukur berdasarkan perubahan optical density pada panjang geliombang 600 nm. Hasil penelitian menunjukkan bahwa pH awal 7 merupakan nilai pH awal yang menghasilkan pertumbuhan yang paling cepat sedangkan pH awal 4 memberikan pertumbuhan yang paling lambat. Suhu yang menghasilkan pertumbuhan paling cepat adalah 30 dan 35 oC sedangkan suhu 40oC menghasilkan pertumbuhan yang paling lambat. Kecepatan agitasi yang menghasilkan pertumbuhan paling cepat adalah 100 rpm dan paling lambat 150 rpm. Kata kunci : Lactococcus lactis, suhu, pH, pertumbuhan 

scholarly journals Towards a function-first framework to make soil microbial ecology predictive

2021 ◽  
Author(s):  
Johannes Rousk ◽  
Lettice Hicks
Keyword(s):  
Microbial Community ◽  
Environmental Factors ◽  
Microbial Communities ◽  
Functional Response ◽  
Community Composition ◽  
Ecosystem Function ◽  
Bacterial Growth ◽  
Response Curve ◽  
Ecosystem Functions ◽  
Soil Microbial

<p>Soil microbial communities perform vital ecosystem functions, such as the decomposition of organic matter to provide plant nutrition. However, despite the functional importance of soil microorganisms, attribution of ecosystem function to particular constituents of the microbial community has been impeded by a lack of information linking microbial function to community composition and structure. Here, we propose a function-first framework to predict how microbial communities influence ecosystem functions.</p><p>We first view the microbial community associated with a specific function as a whole, and describe the dependence of microbial functions on environmental factors (e.g. the intrinsic temperature dependence of bacterial growth rates). This step defines the aggregate functional response curve of the community. Second, the contribution of the whole community to ecosystem function can be predicted, by combining the functional response curve with current environmental conditions. Functional response curves can then be linked with taxonomic data in order to identify sets of “biomarker” taxa that signal how microbial communities regulate ecosystem functions. Ultimately, such indicator taxa may be used as a diagnostic tool, enabling predictions of ecosystem function from community composition.</p><p>In this presentation, we provide three examples to illustrate the proposed framework, whereby the dependence of bacterial growth on environmental factors, including temperature, pH and salinity, is defined as the functional response curve used to interlink soil bacterial community structure and function. Applying this framework will make it possible to predict ecosystem functions directly from microbial community composition.</p>

scholarly journals Statistical Modeling of Environmental Factors on Microbial Urea Hydrolysis Process for Biocement Production

2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
Hamed Khodadadi Tirkolaei ◽  
Huriye Bilsel
Keyword(s):  
Calcium Carbonate ◽  
Environmental Factors ◽  
Bacterial Growth ◽  
Characteristic Curve ◽  
Urea Hydrolysis ◽  
Raw Material ◽  
Specific Rate ◽  
Logarithmic Scale ◽  
Calcium Carbonate Precipitation ◽  
Face Centered

Calcium carbonate is a widely used raw material by many industries. It can be precipitated through microbial process within soil pores as cementitious bonding agent between grains for geotechnical applications. It is called microbially induced calcium carbonate precipitation (MICP). Designing an appropriate biogrout material for injection into soil is essential for controlling the amount, type, time, and place of the biocement production within pores. For this purpose, understanding the active reactions and the kinetics of bacterial growth and urea hydrolysis is necessary. A conductometric method and spectrophotometry were used in this study to, respectively, monitor the urea hydrolysis reaction progress and bacterial growth inS. pasteurii-inoculated urea-NB-NH4Cl solution at different level of the environmental factors that are initial cell concentration, urea concentration, and temperature. Variation in conductivity of the solution versus logarithmic scale of time was depicted as microbial ureolysis characteristic curve (MUCC) through which lag duration, specific rate, and potential of urea hydrolysis at each condition were obtained. Central composite face-centered (CCF) design, which is one of the response surface methodologies, was employed to statistically fit polynomial models explaining the bacterial growth and the characteristics obtained from MUCCs in terms of the environmental factors and their interactions. An optimization analysis based on the urea-normalized responses was also carried out.

Determination of power-time curves of bacterial growth and study of optimum growth temperature and acidity

1995 ◽  
Vol 45 (1-2) ◽  
pp. 93-98 ◽  
Author(s):  
Zhaodong Nan ◽  
Yongjun Liu ◽  
Haitao Sun ◽  
Honglin Zhang ◽  
Shan Qingzhu ◽  
...  
Keyword(s):  
Bacterial Growth ◽  
Growth Temperature ◽  
Optimum Growth ◽  
Optimum Growth Temperature

Combined effect of the growth temperature and salinity of the medium on the accumulation of compatible solutes by Rhodothermus marinus and Rhodothermus obamensis

Extremophiles ◽  
1999 ◽  
Vol 3 (2) ◽  
pp. 163-172 ◽  
Author(s):  
Zélia Silva ◽  
Nuno Borges ◽  
Lígia O. Martins ◽  
Robin Wait ◽  
Milton S. da Costa ◽  
...  
Keyword(s):  
Growth Temperature ◽  
Compatible Solutes ◽  
Combined Effect ◽  
Rhodothermus Marinus

The Combination Decision of the Greenhouse Equipments on the Photosynthesis of Unit Costs on Seedling Production

2012 ◽  
Vol 195-196 ◽  
pp. 1283-1287
Author(s):  
Chu Wang Su ◽  
Chao Yi Wei ◽  
Mei Zhi Xie ◽  
Xian Ming Tang
Keyword(s):  
Environmental Factors ◽  
Environmental Regulation ◽  
Growth Temperature ◽  
Cost Effective ◽  
Optimum Combination ◽  
Price Ratio ◽  
Seedling Production ◽  
Guangxi Province ◽  
Unit Costs ◽  
Regulation Effect

According to the investment charge, number of year for using, regulation effect of environmental factors and controlling costs, the concept of largest photosynthesis of unit costs on seedling production was mentioned. The photosynthesis of unit costs on six typical kinds of greenhouse in the South area of Guangxi Province were calculated and compared. The optimum combination of greenhouse equipments for eucalyptus seedling production showed that the greenhouse with highest quality-price ratio was the plastic greenhouse equipped with the fan pad, followed with that equipped with the mist fog device. In South area of Guangxi Province, due to high temperatures throughout the year, April to October, the average daytime temperature exceeded 25 ,which is above the optimum seedling growth temperature, so cooling effect of greenhouse in cost-effective environmental regulation has became a major factor.

scholarly journals CpxR-Dependent Thermoregulation ofSerratia marcescensPrtA Metalloprotease Expression and Its Contribution to Bacterial Biofilm Formation

2018 ◽  
Vol 200 (8) ◽  
Author(s):  
Roberto E. Bruna ◽  
María Victoria Molino ◽  
Martina Lazzaro ◽  
Javier F. Mariscotti ◽  
Eleonora García Véscovi
Keyword(s):  
Bacterial Growth ◽  
Growth Temperature ◽  
Direct Interaction ◽  
Bacterial Biofilm ◽  
Binding Motif ◽  
Transcriptional Level ◽  
Surface Adhesion ◽  
Content Type ◽  
Bacterial Surface ◽  
Abiotic Surfaces

ABSTRACTPrtA is the major secreted metalloprotease ofSerratia marcescens. Previous reports implicate PrtA in the pathogenic capacity of this bacterium. PrtA is also clinically used as a potent analgesic and anti-inflammatory drug, and its catalytic properties attract industrial interest. Comparatively, there is scarce knowledge about the mechanisms that physiologically govern PrtA expression inSerratia. In this work, we demonstrate that PrtA production is derepressed when the bacterial growth temperature decreases from 37°C to 30°C. We show that this thermoregulation occurs at the transcriptional level. We determined that upstream ofprtA, there is a conserved motif that is directly recognized by the CpxR transcriptional regulator. This feature is found alongSerratiastrains irrespective of their isolation source, suggesting an evolutionary conservation of CpxR-dependent regulation of PrtA expression. We found that inS. marcescens, the CpxAR system is more active at 37°C than at 30°C. In good agreement with these results, in acpxRmutant background,prtAis derepressed at 37°C, while overexpression of the NlpE lipoprotein, a well-known CpxAR-inducing condition, inhibits PrtA expression, suggesting that the levels of the activated form of CpxR are increased at 37°C over those at 30°C. In addition, we establish that PrtA is involved in the ability ofS. marcescensto develop biofilm. In accordance, CpxR influences the biofilm phenotype only when bacteria are grown at 37°C. In sum, our findings shed light on regulatory mechanisms that fine-tune PrtA expression and reveal a novel role for PrtA in the lifestyle ofS. marcescens.IMPORTANCEWe demonstrate thatS. marcescensmetalloprotease PrtA expression is transcriptionally thermoregulated. While strongly activated below 30°C, its expression is downregulated at 37°C. We found that inS. marcescens, the CpxAR signal transduction system, which responds to envelope stress and bacterial surface adhesion, is activated at 37°C and able to downregulate PrtA expression by direct interaction of CpxR with a binding motif located upstream of theprtAgene. Moreover, we reveal that PrtA expression favors the ability ofS. marcescensto develop biofilm, irrespective of the bacterial growth temperature. In this context, thermoregulation along with a highly conserved CpxR-dependent modulation mechanism gives clues about the relevance of PrtA as a factor implicated in the persistence ofS. marcescenson abiotic surfaces and in bacterial host colonization capacity.

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