SAGE KE Bulletin Board

Recent Publication Related to Bacterial Aging Study

14 April 2005

Shi V. Liu

ASM New just published my letter submitted in January 2005. The following is the complete content of the letter. The full citation for this Letter should be as "Liu,S.V. 2005. Single-cell microbiology needs visions. ASM News 71:157-158, 2005" (Copyright by ASM)

Single-Cell Microbiology Needs Visions

In a review published recently in Microbiology and Molecular Biology Reviews (68:538-559, 2004), Brehm-Stecher and Johnson pointed out the need for single-cell microbiology to address the heterogeneity issues compounding the population approach of studying microbiology and summarized recent advances in technologies that have enabled unprecedented efforts of studying microorganisms as single cells. I am glad to see that, after years of appealing for mainstream microbiologists to pay due attention to the importance of individual approaches of studying microorganisms (ASM News 65:185, 1999 and 66:123, 2000; Logical Biology 1:5-16 and 25-31, 2000), this field finally got its appropriate attention. However, I am very disappointed to say that, besides introducing tools and technologies and compiling some application data, this review provided little insight in understanding individual microbial lives.

In my opinion, a lack of suitable technologies is only a minor obstacle for applying the single-cell approach to study microbial life. A "mind constraint" is in fact the greatest cause for ignoring the necessity of studying microbial life on the individual basis. This mind constraint started with some dogmatic views which were based on indirect observations and subjective reasoning but have been reinforced into some "law-like" principles through casual or even irresponsible citations (Logical Biol. 1:5-16 and 25-31, 2000). To promote logical reasoning and judgment in biological research, I launched an Internet-based journal called Logical Biology ( I published most of my unique observations on single bacteria and novel hypotheses of microbial life there, along with some critical reviews and logical and historical analyses on microbiology. The journal has also published original papers on observations of bacterial aging and disclosed the application of a true cell age synchronization methodology. These novel observations and reasoning shed lights into the current debate on cell synchronization methodologies (Trends Biotechnol. 23:9-10, 2005).

I believe that there has been too much emphasis on the role of technologies for the delay or advancement of single-cell microbiology. In my opinion, a lack of insightful vision is the paramount problem in advancing single-cell microbiology, especially when plenty of technologies are available. I also believe that the holy grail of single-cell microbiology is not revealing the differences and identifying the scope of heterogeneity in parameters measured by the population approaches. In fact, the quick and easy process of using population/culture approaches to obtain the average values of some biotic parameters is and should continue to be the strong point of microbiology as compared with macrobiology. The soul and spirit of single-cell microbiology should be reflected in its power to reveal the true causes underlying the variations within a population. I compare most current single-cell studies as the "cross-sectional" type where multiple individual microorganisms are separately measured at the same time. This kind of study may play only a minor role in extending our knowledge of microorganisms because it mainly adds some "standard deviation" type data to the existing knowledge of "averages." In contrast, the "longitudinal" single-cell studies where individual microorganisms are followed for their life time--a time period that should be at least longer than one "cell cycle" (cell reproduction cycle)--would be much more important for reaching a true understanding of microbial lives as single cells (Sci. China 42:644-654, 1999).

Woese recently made a very truthful and pertinent remark about the relationship between technology and vision on the science development. He said that "Science is impelled by two main factors, technological advance and a guiding vision (overview) without the proper technological advances the road ahead is blocked. Without a guiding vision there is no road ahead." (Microbiol. Mol. Biol. Rev. 68:173-186, 2004). Now we have many much advanced technologies for performing research on single cells/ microbial individuals. However, what visions do we have for guiding research in single-cell microbiology?

Shi V. Liu
Eagle Institute of Molecular Medicine
Research Triangle Park, N.C.

Science of Aging Knowledge Environment. ISSN 1539-6150