Why overexpressed proteins are toxic to E.coli ?

A majority of E. coli proteins when overexpressed inhibit its growth, but the reasons behind overexpression toxicity of proteins remain unknown. Understanding the mechanism of overexpression toxicity is important from evolutionary, biotechnological and possibly clinical perspectives. Here we study sequence and functional features of cytosolic proteins of E. coli associated with overexpression toxicity to understand its mechanism. We find that number of positively charged residues is significantly higher in proteins showing

Breaking Discovery: Eighteen species of bacteria found in troposphere (between 8-15 km above the earth)

Microbes  are  said  to be in every part of earth including the hottest (under sea volcanoes)  and coldest (Polar regions) places of earth. What is being studied in Microbiology is those microbes which can be cultured. They constitute less than 1% of the total microbes in the earth.  Can you believe the news that  microbes exist  even in troposphere which is eight kilometres above the earth.  A recent study conducted by Scientists from School of Biology, School of Earth and Atmospheric Sciences, School of Civil and Environmental Engineering, School of Chemical and Biomolecular Engineering of  Georgia Institute of Technology at  Atlanta, USA and Chemistry and Dynamics Branch/Science Directorate, National

A fruit company has made Nonbrowning apple by genetic engineering ( gene silensing)

Apples turn brown when the fruit’s phenolic compounds react with oxygen. This oxidation process is driven by polyphenol oxidase (PPO), an enzyme. When an apple’s cells are ruptured – for example, by bruising, biting or cutting – the browning reaction begins when PPO found in one part of the cell is able to react with phenolic compounds found elsewhere in the cell.

Recent mapping of apple’s genome revealed that PPO is genetically encoded in a diverse, multi-gene family. Apples have at least eight PPO genes, in three main PPO gene families.  To breed a truly nonbrowning apple, all of the active PPO genes must be silenced. Arctic® apples have been genetically engineered to produce little or no PPO enzyme, so cell disruption doesn’t lead to browning.