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Nucleoid contributes to the immortality of bacteria cell lineages

In his doctoral dissertation, MSc Ramakanth Neeli-Venkata provides new insights into the mechanistic role of the nucleoid in the contribution of immortality to the bacteria and further its role as an organizer of the internal cellular structure of bacteria.

Aging is a nearly universal feature of all living organisms. Aging is not confined to higher-level organisms, such as humans, but is also visible in lower-level organisms, such as bacteria. Previous studies have shown that the accumulation of unwanted substances contributes to aging in bacteria.

Interestingly, while previously viewed as disordered ‘bags of enzymes’ that mainly aim to grow and divide, it is now established that bacterial cells are highly organized in a spatio-temporal manner. Advances in microscopy and the use of fluorescent proteins have enabled us to reach such conclusions. Recently, it was hypothesized that the bacterial chromosome, referred to as ‘nucleoid’, plays a key role in such organization.

In his doctoral dissertation, using Escherichia coli as a model organism, Ramakanth Neeli-Venkata investigated and validated the hypothesis that the presence of the nucleoid at midcell is one of the main contributing factors for the ability of E. coli cells to spatially organize their contents. He also demonstrates that this occurs via a phenomenon named ‘nucleoid exclusion’ which forces large, unwanted substances to become located at the cell poles.

“Combined with multiple division events, this results in the creation of ‘renewed’ cells, lacking such unwanted substances that perpetuate the cell lineages,” Neeli-Venkata says.

Neeli-Venkata’s research proves the existence of exclusion of large protein aggregates and aggregate-like clusters from the cell center due to the nucleoid exclusion phenomenon, providing new insights about the mechanistic role of the nucleoid as an organizer of the internal cellular structure of bacteria.

Public defence of a doctoral dissertation on Friday, 10 November

MSc Ramakanth Neeli-Venkata’s doctoral dissertation in the field of biophysics entitled `The Role of Nucleoid Exclusion in the Intracellular Spatial Organization of Escherichia coli’ will be publicly examined at the Faculty of Biomedical Sciences and Engineering of Tampere University of Technology (TUT) in the Tietotalo building, Auditorium TB109 (address: Korkeakoulunkatu 6, Tampere, Finland) at 12 noon on Friday, 10 November 2017. The opponent will be Professor Judith Armitage (University of Oxford, UK). Professor Andre S. Ribeiro from the Faculty of Biomedical Sciences and Engineering of TUT will act as Chairman. 

Ramakanth Neeli-Venkata works as a researcher at the Laboratory of Biosystems Dynamics (LBD) of the Faculty of Biomedical Sciences and Engineering of TUT.

The dissertation is available online at:

Further information: Ramakanth Neeli-Venkata, tel. +358 400980996, e-mail:

News submitted by: Sanna Kähkönen
Keywords: science and research, biomedical sciences and engineering