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Showing posts from December, 2019

Story of Kary Mullis, PCR inventor

'Sometimes a great idea comes to you when you are not looking for it' 'Science is subject to arbitrary fashion'  'Science grows like a weed every year'    Kary Mullis at TED talk. Kary Mullis, inventor of PCR was born on 28 December 1944 in North Carolina, USA. His parents grew up in the foothills of Blue ridge Mountains. And they live near their grandfather’s farm. Kary Mullis was an eight-year-old boy when Watson and Crick published the structure of DNA in 1953. By the time Watson and Crick were awarded Nobel prize, Kary was still busy designing rockets in Georgia Institute of Technology. He was not interested in studying DNA at all. By the time he left Georgia Tech, biologists had already solved the genetic code. It was during his six years at UC, Berkley as a Ph.D. student that changes his mind. After six years at Berkley with a Ph.D., he headed to Kansas to become a writer. He quickly found out he was too young to be a writer and was poor...

Scientists have discovered a bacteriophage that can evade CRISPR-Cas nuclease.

Scientists have discovered a bacteriophage that can evade the CRISPR-Cas system of bacteria. The bacteriophage protects its own DNA by forming a nucleus-like compartment and thus shields its own DNA from the CRISPR nuclease. Bacteria have a various defense system that protects them from Bacteriophages. The most important system was Restriction modification (RM) system and CRISPR Cas system. Virus must evolve to avoid these immune pathways of bacteria that targets nucleic acids. The researchers found that jumbo phages (ФKZ) that target pseudomonas were resistant to CRISPR Cas9. On further investigation, they observed a proteinaceous nucleus-like compartment in which the replication of phages DNA takes place. Proteins that are involve in replication, transcription and recombination are localized within the compartment. The compartment blocks that CRISPR nuclease form targeting DNA. This study was published in the journal Nature. References : A bacteriophages nucleus-lik...

World's first Pig-Monkey chimera created in China

Pig-Monkey chimera A team of researchers from China has created the world’s first Pig-Monkey chimera. The scientists created the chimera by injecting monkey stem cells into the egg of a pig. The embryo  was grown  in vitro and later transferred to a surrogate mother. Two piglets  were delivered  16 weeks later. Detail reports: Chimera is a single organism that has DNA from two separate species or individuals. Here the chimeric organism is created from a pig and a monkey. In this research, they first collected the egg of a pig and was grown in the lab for 5 days for activation. They then inject embryonic stem cells (ESCs) of a monkey to the egg and were  grown for another 48 hours. The embryos were then transferred to a recipient surrogate mother. Two piglets were delivered 16 weeks later. However, the two piglets survive for just 28 days due to which it was not possible to observe whether the chimera can develop into mature functional cells. ...