The budding yeast, Saccharomyces cerevisiae, is a prime organism for studying fundamental cellular processes, with the functions of many proteins important in the cell cycle and signaling networks found in human biology having first been discovered in yeast.
Now, scientists from New York University have now developed a sophisticated assay to track cell growth at very low nutrient concentrations. The assay uses time-lapse microscopy to monitor individual yeast cells undergoing a small number of divisions to form microcolonies.
The assay can measure the lag times and growth rates of as many as 80,000 individual microcolonies in a single 24-hour experiment, opening up a powerful new high-throughput tool to study the complex interplay between cell growth, division and metabolism under environmental conditions that are likely to be ecologically relevant but had previously been difficult to study in the laboratory.
The researchers studied growth rates and lag times in both lab strains and wild yeast by varying the amount of its prime carbon food source, glucose. They confirmed the prediction made over 60 years ago by Noble-prize-winning biologist Jacques Monod regarding changes in microbial growth rates with limited nutrients (the Monod equation). They also found significant differences among strains in both the average lag response (the amount of time it takes to transition from cell quiescence to restarting cell growth) and average growth rates in response to different environmental conditions.
In addition to average differences between strains and conditions, the powerful assay revealed metabolic differences among cells of the same strain in the same environment. Moreover, yeast strains differed in their variances in growth rate. According to the study's lead author, Naomi Ziv, "Heterogeneity among genetically identical cells in the same environment is a topic of increasing interest in biology and medicine. The different strain variances we see suggest that the extent of nongenetic heterogeneity is itself genetically determined."
Further investigations could pave the way to a more complete understanding of the genetics and metabolomics of cell growth in yeast and the underlying mechanisms relevant to other settings in which cells face challenging conditions, such as cancer progression and the evolution of drug resistance.
To access the full online article: http://mbe.oxfordjournals.org/content/early/2013/08/11/molbev.mst138.abstract
Media sources:David Gresham
Unlike genomic DNA, the mitochondrial genome is unique inherited only through the mother, is small in size, and has a high mutation rate. Researchers Longli Kang, Li Jin et al. have sequenced 76 Sherpa individuals' complete mitochondrial genomes living in Zhangmu Town, Tibet, and found two mutations that were specific to the Sherpa population. The authors suggest that variants for one recent mutation in particular that was introduced into the Sherpa population about 1,500 years ago, A4e3a, that may be an important adaptation for low oxygen environments, or hypoxic conditions. This mutation is found in an "entry enzyme" stage in the mitochondrial respiratory complex, which may explain the importance of the role of mitochondria in the Sherpa population's ability to adapt to the extreme Himalayan environment.
The authors also shed light on the demographic history of Sherpa population size over evolutionary time, showing a significant expansion from 3,000 to 23,000 around 50,000 years ago, followed by a very recent bottleneck in the past several hundred years that reduced the population from 10,000 to 2,400, matching known historical migration patterns.
Media source:Prof. Li Jin
Joe Caspermeyer | EurekAlert!
Novel mechanisms of action discovered for the skin cancer medication Imiquimod
21.10.2016 | Technische Universität München
Second research flight into zero gravity
21.10.2016 | Universität Zürich
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.
In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...
'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.
Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
21.10.2016 | Health and Medicine
21.10.2016 | Information Technology
21.10.2016 | Materials Sciences