Dear Steemians,
I can not believe that it is my fourth week already. It has been good to put forward some decent content on Molecular Biology and recent discoveries in the field. It has been fun to interact with people from the #steemSTEM community. I have been reading the articles and the content is really on par with the best out of the platform. I really loved 
With Out further Adieu, let's check out what cool stuff has been happening in the world of Molecular Biology. I am excited myself with this weeks edition, I will give the reason at the end of the post.
The weekly roundup December 17, 2017ª.
- Memory T-cells: Origins unveiledd.
It has been a well-established fact that vaccinations help bolster the immune system from any attacks by harmful pathogens. There have been extensive studies classifying subsets of immune cells that help establish this response. The presence of memory T cells helps the system to remember 'previous attacks' and react to any subsequent attacks. But, How exactly this memory is remembered was not clearly understood.
In this week's issue of Nature, two groups of researchers solved this longstanding puzzle using two different approaches and have come to similar conclusions.
- The authors identified a key enzyme that was responsible for de novo DNA methylation during an immune response.
- The enzyme Dnmt3a leaves chemical modifications known as methylation on the DNA level which seems to leave marks on the T-cell genome. These marks are likely responsible for memory; It is almost akin a tape-recorder leaving magnetic imprints on the tape.
- The main observation was that "In effector T cells that are differentiating into memory cells, the methylation of genes expressed in the naive state can be removed in a cell-division-independent process that might drive the re-expression of naive-associated genes, which could, in turn, be needed to establish or maintain the long-lived memory-cell population."
- Both studies conclude that memory T cells no longer express effector molecules and the genes encoding for this molecule remain in a state of low methylation.
- The paper by Akondy and her team show that memory T-cells remain as long as 10 years after vaccination in the system.
- Both studies show that The memory T-cells arise from a population of effector T-cells but their effector genes are turned off. This retains some memory and DNA modifications seem to play a central role in the retention of memory phenotype. Upon the pathogen-reinfection; Epigenetic landscape changes and the memory T-cells may re-acquire effector functions.
The Papers can be accessed at Nature. Akondy et al. Youngblood et al. A news article accompanied by the same issue can be read here
- A fungus helps a virus: A story of love between two partners in crime.
In an article in e-Life by George Demopoulos and his team; The scientists have discovered an interesting connection between the propagation of a virus and how a gut fungus helps the virus in the host.
It is well known that Dengue is wreaking havoc in the tropical belt of the world. Its prevalence has been on a steady rise. In this link; One can see the reported cases of dengue in past 3 months. With a global burden like this; scientists are tackling why certain Aedes aegypti mosquitoes are more affected by the virus.
It seems that; after consuming blood from an infected individual The viruses go through the mosquito's midgut. There the fungi of Talaromyces species downregulate digestive enzymes by exposing the mosquitoes to secreted factors. This, in turn, helps the viruses stay 'active' rather than getting digested by proteases/enzymes of the gut. In a way, the articles show how one fungi's survival helps the virus survival.
The article can be read at e-Life.
- Limits of Energy expenditure: How an immune system molecule limits thermogenesis.
For a few years now, there has been increasing evidence that a single molecule has several functions outside the 'discovered class'. It was initially thought that proteins/molecules have a singular function but that dogma is continuously been proven wrong.
An article in the journal Cell has shown very interesting results. A well known anti-inflammatory cytokine IL-10 has been shown to be responsible for controlling energy expenditure and adipose thermogenesis. The authors observe that Mice lacking IL-10 have increased energy expenditure and adipose thermogenesis. Upon conducting functional assays, they find that In IL-10 acts on IL-10Rα to antagonize the adrenergic tone. The mechanism by which this occurs is by alteration of chromatin landscape; the signalling involves C/EBPβ and ATF occupancy in adipose tissues.
In a therapeutic context, it may be a viable option that " blockade of IL-10 receptor signalling in fat could represent a tractable approach to de-repress thermogenic gene expression in a therapeutic context."
The article by Rajbhandari and colleagues can be read here
- Making CRISPR inducible: A new development in genome editing technologies.
We have over the past articles discussed a bit on CRISPR. In fact, In the latest 
In a recent article in Nucleic Acids Research; Researchers led by Runna Ai Yu Wang from China have described a new inducible CRISPR/Cas9 system. They have brilliantly engineered a series of hybrid drug-inducible CRISPR/Cas9 molecules. The authors may have been inspired by Cre/Lox inducible mice; Like the mic, they have used a mutated human estrogen receptor and grafted on to multiple CRISPR/CAS9 systems. This, in turn, renders them to be inducible to 4-hydroxytamoxifen.
In short; The authors now show a system by which adding 4-OHT induces the editing and can be used to target multiple loci.
The article can be read at this Link.
Image Sources:
T-cells Attcking HIV: NIAID/Wikimedia
Zika Virus Cryo-EM: Sirohi, D., Chen, Z., Sun, L., Klose, T., Pierson, T., Rossmann, M. and Kuhn, R. (2016). The 3.8Å resolution cryo-EM structure of Zika virus. DOI: 10.2210/pdb5ire/pdb Article Link Image Link and Link
Anopheles mosquito: Image by Paul Howell. Link
Please take time to visit the image galleries as it will encourage the respective authors. This article includes screenshots of the linked articles also. It is not my own work, Please check the articles for further details.
To be Continued!
ª : I usually publish this weekly article on Sundays. But Due to Christmas vacations heading up, I got busy to wrap my regular projects and try to unwind for the rest of the year. I will try to write another before the year ends, But I am not sure if I can have enough time. But rest assured I will come up with more #steemSTEM articles in the year ahead.
If you made it to this far; Merry Christmas and A Happy New Year.
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GIF by Nitesh9
