Researchers identify workings of L-form bacteria

Oct 13, 2009

Researchers at the Johns Hopkins Bloomberg School of Public Health have for the first time identified the genetic mechanisms involved in the formation and survival of L-form bacteria. Their findings are described in a study published October 6 in the journal PLoS ONE.

L-form bacteria, which were first discovered in the 1930s, are morphological variants of classical bacteria that lack a cell wall. Under specialized growth conditions L-form bacteria are capable of forming a typical "fried egg" colony, which resembles a fried egg rather than the smooth appearance of a classic bacteria colony. These bacteria are believed to form in response to cell wall stress from certain antibiotics or the body's immune attack, and are suspected to be associated with antibiotic-resistant and persistent infections, as well as certain diseases.

"Our study provides new insight about the molecular basis of L-form bacteria, which was not previously known," said Ying Zhang, MD, PhD, senior author of the study and professor in the Bloomberg School's W. Harry Feinstone Department of and Immunology. "These findings establish the framework for future research on how the identified genes and pathways interact leading to L-forms. They also have important implications for understanding the emergence of and bacterial persistence and for developing new drugs and vaccines targeting such persistent L-form bacteria for improved ."

According to Zhang, L-form bacteria are difficult to study because their biology and the circumstances favoring the transition of classical bacteria into L-forms are not fully understood. In addition, specialized culture conditions are required for study. Most research on L-form bacteria was largely abandoned in the 1980s before modern molecular tools could be applied, but renewed interest in L-form bacteria has recently emerged.

For the study, Zhang and colleagues William Glover, a graduate student at the Bloomberg School, and Yanqin Yang, a senior program analyst with the Johns Hopkins School of Medicine, conducted a genome-wide gene expression analysis of L-form colonies of E. coli bacteria. They identified interesting stress genes and pathways that overlap with persisters and biofilm bacteria. Furthermore, the authors carried out mutant screens and identified three groups of mutants with varying degrees of defect in L-form formation or survival compared to classic colonies of E. coli. Mutants that showed complete lack of L-form growth belonged to pathways related to cell envelope stress, DNA repair, iron regulation and outer membrane biogenesis. The mutants could be restored to L-form growth by their respective wild type genes, confirming their role in L-form formation or survival.

Source: Johns Hopkins University Bloomberg School of Public Health (news : web)

Explore further: Top Japan lab dismisses ground-breaking stem cell study

add to favorites email to friend print save as pdf

Related Stories

Genes that make bacteria make up their minds

Mar 30, 2009

Bacteria are single cell organisms with no nervous system or brain. So how do individual bacterial cells living as part of a complex community called a biofilm "decide" between different physiological processes (such as movement ...

Resistant gut bacteria will not go away by themselves

Jun 19, 2007

E. coli bacteria that have developed resistance to antibiotics will probably still be around even if we stop using antibiotics, as these strains have the same good chance as other bacteria of continuing to colonise the gut, ...

Small molecule triggers bacterial community

Dec 22, 2008

While bacterial cells tend to be rather solitary individuals, they are also known to form intricately structured communities called biofilms. But until now, no one has known the mechanisms that cause isolated bacteria to ...

The structure of resistance

Feb 22, 2008

A team of scientists from the University Paris Descartes has solved the structure of two proteins that allow bacteria to gain resistance to multiple types of antibiotics, according to a report in EMBO reports this month. ...

Recommended for you

Top Japan lab dismisses ground-breaking stem cell study

Dec 26, 2014

Japan's top research institute on Friday hammered the final nail in the coffin of what was once billed as a ground-breaking stem cell study, dismissing it as flawed and saying the work could have been fabricated.

Research sheds light on what causes cells to divide

Dec 24, 2014

When a rapidly-growing cell divides into two smaller cells, what triggers the split? Is it the size the growing cell eventually reaches? Or is the real trigger the time period over which the cell keeps growing ...

Locking mechanism found for 'scissors' that cut DNA

Dec 24, 2014

Researchers at Johns Hopkins have discovered what keeps an enzyme from becoming overzealous in its clipping of DNA. Since controlled clipping is required for the production of specialized immune system proteins, ...

Scrapie could breach the species barrier

Dec 24, 2014

INRA scientists have shown for the first time that the pathogens responsible for scrapie in small ruminants (prions) have the potential to convert the human prion protein from a healthy state to a pathological ...

Extracting bioactive compounds from marine microalgae

Dec 24, 2014

Microalgae can produce high value health compounds like omega-3s , traditionally sourced from fish. With declining fish stocks, an alternative source is imperative. Published in the Pertanika Journal of Tr ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.