Written by Written by Samuel Xin Zher Low, Zhen Qin Aw, Bryan Zong Lin Loo, Kun Cheng Lee, Jack Si Hao Oon, Chin How Lee, Maurice Han Tong Ling
Parent Category: Year 2013, Volume 5
Category: Year 2013, Volume 5, Issue 1, January-March 2013
Background: Escherichia coli is a widely studied prokaryotic system. A recent study had demonstrated that reduced growth of E. coli after extended culture in Luria-Bertani broth is a result of depletion of fermentable sugars but able to sustain extended cell culture due to the presence of amino acids, which can be utilized as a carbon source. However, this had not been demonstrated in other media. The study aimed to determine the growth and viability of E. coli ATCC 8739 in 3 different media, Nutrient Broth (NB), Brain Heart Infusion (BHI) and Luria-Bertani Broth (LB) over 11 weeks.
Methods: Growth of E. coli ATCC 8739 was determined by optical density. Viability was determined by serial dilution/spread-plate enumeration. After 11 weeks, the media were exhausted by repeated culture. Glucose was added to the exhausted media to determine whether glucose is the growth-limiting factor.
Results: Our results showed that cell density in all 3 media increased to about 1 x 109 cells/ml by the end of week 1, from the inoculation density of 2.67 x 105 cells/ml, peaked at about 1 x 1013 cells/ml at week 4, before declining to about 5 x 107 cells/ml at week 7. Cell density is highly correlated to genomic DNA content (r2 = 0.93) but poorly correlated to optical density (r2< 0.2). Our results also showed that the spent media were able to support further growth after glucose-supplementation.
Conclusion: NB, LB and BHI are able to support extended periods of culture and glucose depletion is the likely reason for declining cell growth.
Key words: Escherichia coli (E. coli), Extended culture, Genomic DNA content, Glucose
Santé NikeAir Jordan 1 Retro High OG 'Chicago' White and Black-Varsity Red For Sale
The most recent editorial (June 2021)
Ethics of Publishing Case Reports: Do We Need Ethics Approval and Patient Consent?
An editorial by Dr. Mehrdad Jalalian
The worldwide spread of COVID-19 as an emerging, rapidly evolving situation, and the dramatic need of urgent medicine or vaccine, has rapidly brought new hypotheses for pathophysiology and potential medicinal agents to the fore. It is crucial that the research community provide a way to publish this research in a timely manner.
To contribute to this important public health discussion, the Electronic Physician Journal is excited to announce a fast-track procedure to help researchers publish their articles on COVID-19 related subjects that fall under the broad definition of public health, internal medicine, and pharmacology. We are especially welcome to all hypotheses about the pathological basis of the COVID-19 infection and the possible characteristics of potential medicine and vaccine. Submit your manuscript here
Our previous editorial (June 2020)
Lessons from COVID-19 pandemic and the Morocco’s success story.
An editorial by Dr. Benksim Abdelhafid (Morocco)
The 6th World Conference on Research Integrity (WCRI) is to be held on June 2-5, 2019 in Hong Kong.
The WCRI is the largest and most significant international conference on research integrity. Since the first conference in Lisbon in 2007, it has given researchers, teachers, funding agencies, government officials, journal editors, senior administrators, and research students opportunities to share experiences and to discuss and promote integrity in research. Read more:
TDR Clinical Research and Development Fellowships
Call for applications
Deadline for submission: 7 March 2019, 16:00 (GMT)
TDR provides fellowships for early- to mid-career researchers and clinical trial staff (e.g. clinicians, pharmacists, medical statisticians, data managers, other health researchers) in low- and middle-income countries (LMICs) to learn how to conduct clinical trials. Read more:
Meta-Analysis Workshops in New York, USA, and London, UK, in April and May 2019
Don't miss this exceptional opportunity to learn how to perform and report a Meta-analysis correctly. Two Meta-analysis workshops are organized in April and May 2019 by Dr. Michael Borenstein in New York, USA (April 08-10, 2019) and London, UK (May 27-29).
About the Instructor
Dr. Michael Borenstein, one of the authors of Introduction to Meta-Analysis, is widely recognized for his ability to make statistical concepts accessible to researchers as well as to statisticians. He has lectured widely on meta-analysis, including at the NIH, CDC, and FDA. Read more: