Synthetic Organism
23-Jan-2017: Scientists create world’s first stable semi-synthetic organism.
Scientists at The Scripps Research Institute (TSRI) have announced the development of the first stable semisynthetic organism. Building on their 2014 study in which they synthesized a DNA base pair, the researchers created a new bacterium that uses the four natural bases (called A, T, C and G), which every living organism possesses, but that also holds as a pair two synthetic bases called X and Y in its genetic code.
While applications for this kind of organism are still far in the future, the researchers say the work could be used to create new functions for single-celled organisms that play important roles in drug discovery and much more.
During initial research in 2014, these E. coli couldn't keep the base pair in their code indefinitely as they divided. The X and Y base pair was dropped over time, limiting the ways the organism could use the additional information possessed in their DNA. But, the new single-celled organism can hold on indefinitely to the synthetic base pair as it divides.
A New Use for CRISPR-Cas9
Finally, the researchers set up a "spell check" system for the organism using CRISPR-Cas9, an increasingly popular tool in human genome editing experiments. But instead of editing a genome, the researchers took advantage of CRISPR-Cas9's original role in bacteria.
The genetic tools in CRISPR-Cas9 (a DNA segment and an enzyme) originated in bacteria as a kind of immune response. When a bacterium encounters a threat, like a virus, it takes fragments of the invader genome and pastes them into its own genome -- a bit like posting a "wanted" poster on the off chance it sees the invader again. Later, it can use those pasted genes to direct an enzyme to attack if the invader returns.
Knowing this, the researchers designed the organism to see a genetic sequence without X and Y as a foreign invader. A cell that dropped X and Y would be marked for destruction, leaving the scientists with an organism that could hold on to the new bases. It was like the organism was immune to unnatural base pair loss. The semisynthetic organism was thus able to keep X and Y in its genome after dividing 60 times, leading the researchers to believe it can hold on to the base pair indefinitely.
This work is only in single cells and is not meant to be used in more complex organisms. The actual applications for this semisynthetic organism are "zero" at this point. So far, scientists can only get the organism to store genetic information.
Next, the researchers plan to study how their new genetic code can be transcribed into RNA, the molecule in cells needed to translate DNA into proteins. This study lays the foundation for what we want to do going forward.
Mesentery
3-Jan-2017: Mesentery: The Human Body’s new organ
Scientists have discovered a new organ in human body called mesentery. Located in our abdominal cavity, the mesentery is a belt of tissue that holds our intestines in place. While anatomists knew it was there, it was always thought to be composed of several different segments, as opposed to being one single structure. This knocked it out of contention for organ status, as our bodily organs must be continuous, as well as provide some vital function to our anatomy.
A new study from researchers at the University Hospital Limerick reveals that the mesentery is actually one single band of tissue, beginning at the pancreas and continuing down through the small intestine and colon, wrapping around these vital organs to hold them tight and help them maintain their structure. It is made of a folded-over ribbon of peritoneum, a type of tissue usually found lining the abdominal cavity.
The mesentery is highly integrated with the intestine, and is located in an area of the human body that has not been fully explored.
In apes and other creatures that walk on all fours, the structure of the mesentery, and the organs it supports, is slightly different, which affects the layout of their guts. Understanding how and why our digestive system is arranged the way it is could be crucial to our understanding of diseases like Crohn’s and irritable bowel syndrome.
G Protein-Coupled Receptors (GPCRs)
1-Jan-2017: Drug discovery for GPCR signalling made easy by IIT Kanpur
Researchers have shown that the regulation of G Protein-Coupled Receptors (GPCRs) by new drugs can be simpler than generally thought. It can be mediated by engaging only the end of the receptor, which is called the tail of the receptor.
With this discovery, finding new drugs that bind to G Protein-Coupled Receptors (GPCRs) which are central to almost every physiological process in our body such as vision, taste, immune response and cardiovascular regulation becomes easier.
Nearly 50% of prescription drugs currently available in the market for the treatment of blood pressure, heart failure, diabetes, obesity, cancer and many other human diseases target GPCR receptors. All these drugs bind to their respective receptors and either activate or stop their signalling.
General understanding is that effector proteins have to simultaneously bind at two sites — the tail of the receptor and the core of the receptor — for the drug to become effective in pulling the receptor inside the cell. Through specific engineering of the receptor researchers basically disrupted one of the two binding sites, namely the core of receptor. They found that even without the second site, the protein was able to pull the receptor inside the cell by binding just to the tail of the receptor. There is a key region in the core which the researchers genetically deleted thereby making the core of the receptor ineffective.