Cellular microbiology is a discipline that bridges microbiology and cell biology. The term "cellular microbiology" was coined by the authors of the book of the same title published in 1996. Cooperation and mutual dependency between microbiology and cell biology had been increasing in the years before that, and the emergence of a new discipline had been suggested and discussed in several scientific conferences. Cellular microbiology attempts to use

pathogen In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ ...

microorganism A microorganism, or microbe,, ''mikros'', "small") and ''organism'' from the el, ὀργανισμός, ''organismós'', "organism"). It is usually written as a single word but is sometimes hyphenated (''micro-organism''), especially in olde ...

s as tools for cell-biology research, and to employ cell-biology methods to understand the pathogenicity of microorganisms.

Toxin A toxin is a naturally occurring organic poison produced by metabolic activities of living cells or organisms. Toxins occur especially as a protein or conjugated protein. The term toxin was first used by organic chemist Ludwig Brieger (1849 ...

s and

virulence factor Virulence factors (preferably known as pathogenicity factors or effectors in plant science) are cellular structures, molecules and regulatory systems that enable microbial pathogens (bacteria, viruses, fungi, and protozoa) to achieve the following ...

s from microbes have been used for decades to influence processes in

eukaryotic Eukaryotes () are organisms whose Cell (biology), cells have a cell nucleus, nucleus. All animals, plants, fungi, and many unicellular organisms, are Eukaryotes. They belong to the group of organisms Eukaryota or Eukarya, which is one of the ...

cells and to study them. It has increasingly appeared that applying a purified toxin on a cell does not always provide the complete picture, and that understanding the role of the toxin in pathogenicity, the way the toxin promotes the microbe, the way the toxin is produced and the

co-evolution In biology, coevolution occurs when two or more species reciprocally affect each other's evolution through the process of natural selection. The term sometimes is used for two traits in the same species affecting each other's evolution, as well ...

of the toxin and its host-cell counterparts, is crucial. Numerous eukaryotic cellular processes have been clarified using microbial "tools". A major subject in this category is the

cytoskeleton The cytoskeleton is a complex, dynamic network of interlinking protein filaments present in the cytoplasm of all cells, including those of bacteria and archaea. In eukaryotes, it extends from the cell nucleus to the cell membrane and is com ...

. Many microbes modify and influence the synthesis or degradation of the host-cell cytoskeleton, in particular the

actin Actin is a family of globular multi-functional proteins that form microfilaments in the cytoskeleton, and the thin filaments in muscle fibrils. It is found in essentially all eukaryotic cells, where it may be present at a concentration of ov ...

network. Intracellular microbes, such as the

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of prokaryotic microorganisms. Typically a few micrometr ...

'' Salmonella'' and ''

Shigella ''Shigella'' is a genus of bacteria that is Gram-negative, facultative anaerobic, non-spore-forming, nonmotile, rod-shaped, and genetically closely related to '' E. coli''. The genus is named after Kiyoshi Shiga, who first discovered it in 1 ...

'', elicit actin

polymerization In polymer chemistry, polymerization (American English), or polymerisation (British English), is a process of reacting monomer molecules together in a chemical reaction to form polymer chains or three-dimensional networks. There are many fo ...

in host cells that otherwise do not internalize microbes (non-

phagocyte Phagocytes are cells that protect the body by ingesting harmful foreign particles, bacteria, and dead or dying cells. Their name comes from the Greek ', "to eat" or "devour", and "-cyte", the suffix in biology denoting "cell", from the Greek ...

s). This causes the formation of projections that eventually engulf the bacteria. Bacteria such as ''

Yersinia ''Yersinia'' is a genus of bacteria in the family Yersiniaceae. ''Yersinia'' species are Gram-negative, coccobacilli bacteria, a few micrometers long and fractions of a micrometer in diameter, and are facultative anaerobes. Some members of ''Yer ...

'' inhibit actin polymerization in phagocytes, thereby preventing their uptake. Cellular microbiology tries to understand these processes and how they promote

infection An infection is the invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmissible disease or communicable dis ...

. Other eukaryotic processes that microbes influence and that are researched using microbes are signal transduction,

metabolism Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run c ...

, vesicle trafficking,

cell cycle The cell cycle, or cell-division cycle, is the series of events that take place in a cell that cause it to divide into two daughter cells. These events include the duplication of its DNA (DNA replication) and some of its organelles, and sub ...

and

transcriptional regulation In molecular biology and genetics, transcriptional regulation is the means by which a cell regulates the conversion of DNA to RNA (transcription), thereby orchestrating gene activity. A single gene can be regulated in a range of ways, from al ...

, to name but a few. Recently, the field of Cellular Microbiology has been expanded to incorporate investigation of the cell biology of microbes themselves.NIH Cellular and Molecular Microbiology (CMM) training program (http://www.mc.vanderbilt.edu/reporter/index.html?ID=988) "The field of cellular microbiology is a coalescence of two fields: molecular microbiology and cell biology," said Professor Jacek Hawiger, Chair of Microbiology and Immunology at Vanderbilt University. Particularly in the case of bacterial cells, new technology is starting to be used to reveal a high level of organization within the bacterial cells themselves. For example, high-resolution fluorescence microscopy and atomic force microscopy are both being used to show just how sophisticated bacterial cells are.

References

{{DEFAULTSORT:Cellular Microbiology Microbiology Cell biology