WeitzGroup@GeorgiaTech
January 05, 2009
Dr. Olga Symonova joined the Weitz group as a postdoctoral researcher. Olga received her BS and MS in Ukraine and her PhD in Computer Science from the University of Trento, Italy. Her PhD research was focused on the description and retrieval of 3D models. Here at Georgia Tech, Olga will work on characterizing the shape and structure of root networks as part of a newly awarded NSF grant, "GEPR: Genome wide analysis of root traits",with Philip Benfey (Duke University) and other collaborators at Duke, NC State, Cornell, and Penn State.
October 22, 2008
Earlier this year, the Weitz group proposed a mechanism to explain how bacterial viruses can make collective decisions inside cells. Viruses can perform a form of "quorum sensing" to sense changes in viral genome copy number within multiply infected hosts. The basis of this mechanism is the nonlinear effect of copy number variation on gene expression. In a paper published this week in the Early Edition of PNAS, our group demonstrated that copy number controls expression outcome in a variety of commonly found gene regulatory motifs. The key finding is that the outcome of a gene regulatory network depends on the copy number of genes and component modules, in addition to the topology of the network and environmental effects. From the emergence and evolution of gene duplicates to the behavior of multiply infected cells,our group will continue to investigate how copy number modifies the dynamics of gene regulation.
August 15, 2008
A new study suggests that bacteria-infecting viruses called phages can make collective decisions about whether to kill host cells immediately after infection or enter a latent state to remain within the host cell.
The research, published in the September 15 issue of the Biophysical Journal, shows that when multiple viruses infect a cell, this increases the number of viral genomes and therefore the overall level of viral gene expression. Changes in viral gene expression can have a dramatic nonlinear effect on gene networks that control whether viruses burst out of the host cell or enter a latent state.
News releases: GaTech, Physorg.com, Science Daily, Biology News Net.
Read the full article online on Biophysical Journal.
August 15, 2008
Loukia Lili joined our group as she entered a PhD program in Biology, GaTech. Originally from Greece, Loukia had been studying Mathematical Biology, focusing on deterministic models, at University of Bath, UK. Here she hopes to learn "real" Biology.
August 04, 2008
The James S. McDonnell Foundation (JSMF) has awarded Dr. Weitz a Research Award for Studying Complex Systems as part of their 21st Century Science Initiative. Dr. Weitz and his group will investigate "Mechanisms and evolution of complex life history traits in bacterial viruses".
More information about this proposal can be found here.
A complete list of funded grants can be found here.
July 10, 2008
Each year the School of Mathematics at Georgia Tech recognizes its outstanding junior and senior with prizes. This year AJ Friend was named as the 2007 Math junior of the year. AJ has actively participated in research as an undergraduate. Prior to joining the group, AJ conducted research examining the degree of partisanship and power networks of the U.S. House of Representatives.
June 20, 2008
We have developed a mathematical theory of how bacterial viruses can make collective decisions concerning the fate of infected cells. For many bacterial viruses, the choice of whether to kill host cells or enter a latent state depends on the multiplicity of coinfection. Coinfection introduces a variable number of phage DNA copies into a host cell which direct the host to produce phage mRNAs and proteins. The distinct phage genomes are coupled via a common pool of transcriptional regulators. When viral regulation of cell fate includes nonlinear feedback loops, this coupling can lead to dramatic changes in steady state gene expression. Hence, we suggest that deterministic decisions can be reached, e.g.,lysis or latency, depending on the cellular multiplicity of infection, in agreement with molecular studies of the decision circuit within phage lambda.
Read the full article online on Biophysical Journal BioFast website.
Read Nature's coverage: Virology: Collective calm.
May 05, 2008
Two undergraduate students joined the group as undergraduate summer research program in Quantitative Systems Biology and Mathematical Biology sponsored by NSF. Sophia Fisher from School of Biology will conduct her research in ecological models of viruses and phage counting experiments. AJ Friend from School of Mathematics will focus on switching behaviors of viruses.
February 12, 2008
Dr. Takeshi Miki from Center for Ecological Research, Kyoto University, Japan, visited our group for possible collaboration. His interests cover the dynamics of protists, phage and bacteria, and microbial decomposition and biodiversity.
January 16, 2008
Our group hosted the "Viral Paradigm Workshop" here on Georgia Tech campus. It was a great chance to meet people with different backgrounds and ideas. Many renowned scientists as well as postdocs and graduate students discussed the theoretical and computational tools to describe the viral world. Topics ranged from viral dynamics within a cell to ecological and epidemiological impact of viruses.
