by Saxena A, Mukherjee U, Kumari R, Singh P, Lal R.
"The amalgamation of the research efforts of biologists, chemists and geneticists led by scientists at the Department of Zoology, University of Delhi has resulted in the development of a novel rifamycin derivative; 24-desmethylrifampicin, which is highly effective against multi-drug resistant (MDR) strains of Mycobacterium tuberculosis. The production of rifamycin analogue was facilitated by genetic-synthetic strategies that have opened an interdisciplinary route for the development of more such rifamycin analogues aiming at a better therapeutic potential. The results of this painstaking effort of nearly 25 years of a team of students and scientists led by Professor Rup Lal have been recently published in the Journal of Biological Chemistry (www.jbc.org/content/289/30/21142.long). This strategy can now find applications for developing newer rifamycin analogues that can be harnessed to overcome the problem of MDR, extensively drug resistant (XDR) and totally drug resistant (TDR) M. tuberculosis."
"Synthetic cellular logic gates are primarily built from gene circuits owing to their inherent modularity. Single proteins can also possess logic gate functions and offer the potential to be simpler, quicker, and less dependent on cellular resources than gene circuits. However, the design of protein logic gates that are modular and integrate with other cellular components is a considerable challenge. As a step toward addressing this challenge, we describe the design, construction, and characterization of AND, ORN, and YES logic gates built by introducing disulfide bonds into RG13, a fusion of maltose binding protein and TEM-1 β-lactamase for which maltose is an allosteric activator of enzyme activity. We rationally designed these disulfide bonds to manipulate RG13’s allosteric regulation mechanism such that the gating had maltose and reducing agents as input signals, and the gates could be toggled between different gating functions using redox agents, although some gates performed sub optimally."
by Wen Xue,Sidi Chen,Hao Yin,Tuomas Tammela,Thales Papagiannakopoulos,Nikhil S. Joshi, Wenxin Cai,Gillian Yang,Roderick Bronson,Denise G. Crowley,Feng Zhang,Daniel G. Anderson,Phillip A. Sharp& Tyler Jacks
"The study of cancer genes in mouse models has traditionally relied on genetically-engineered strains made via transgenesis or gene targeting in embryonic stem cells1. Here we describe a new method of cancer model generation using the CRISPR/Cas (clustered regularly interspaced short palindromic repeats/CRISPR-associated proteins) system in vivo in wild-type mice. We used hydrodynamic injection to deliver a CRISPR plasmid DNA expressing Cas9 and single guide RNAs (sgRNAs)2, 3, 4 to the liver that directly target the tumour suppressor genes Pten (ref. 5) and p53 (also known as TP53 and Trp53) (ref. 6), alone and in combination. CRISPR-mediated Pten mutation led to elevated Akt phosphorylation and lipid accumulation in hepatocytes, phenocopying the effects of deletion of the gene using Cre–LoxP technology7, 8. Simultaneous targeting of Pten and p53 induced liver tumours that mimicked those caused by Cre–loxP-mediated deletion of Pten and p53. DNA sequencing of liver and tumour tissue revealed insertion or deletion mutations of the tumour suppressor genes, including bi-allelic mutations of both Pten and p53 in tumours. Furthermore, co-injection of Cas9 plasmids harbouring sgRNAs targeting the β-catenin gene and a single-stranded DNA oligonucleotide donor carrying activating point mutations led to the generation of hepatocytes with nuclear localization of β-catenin. This study demonstrates the feasibility of direct mutation of tumour suppressor genes and oncogenes in the liver using the CRISPR/Cas system, which presents a new avenue for rapid development of liver cancer models and functional genomics."
by Nithya Srinivasan,Maniraj Bhagawati,Badriprasad Ananthanarayanan& Sanjay Kumar
"Grafting polymers onto surfaces at high density to yield polymer brush coatings is a widely employed strategy to reduce biofouling and interfacial friction. These brushes almost universally feature synthetic polymers, which are often heterogeneous and do not readily allow incorporation of chemical functionalities at precise sites along the constituent chains. To complement these synthetic systems, we introduce a biomimetic, recombinant intrinsically disordered protein that can assemble into an environment-sensitive brush. This macromolecule adopts an extended conformation and can be grafted to solid supports to form oriented protein brushes that swell and collapse dramatically with changes in solution pH and ionic strength. We illustrate the value of sequence specificity by using proteases with mutually orthogonal recognition sites to modulate brush height in situ to predictable values. This study demonstrates that stimuli-responsive brushes can be fabricated from proteins and introduces them as a new class of smart biomaterial building blocks."
Advances in DNA synthesis have enabled the construction of artificial genes, gene circuits, and genomes of bacterial scale. Freedom in de-novo design of synthetic constructs provides significant power in studying the impact of mutations in sequence features, and verifying hypotheses on the functional information that is encoded in nucleic and amino acids. To aid this goal, a large number of software tools of variable sophistication have been implemented, enabling the design of synthetic genes for sequence optimization based on rationally defined properties. The first generation of tools dealt predominantly with singular objectives such as codon usage optimization and unique restriction site incorporation. Recent years have seen the emergence of sequence design tools that aim to evolve sequences toward combinations of objectives. The design of optimal protein coding sequences adhering to multiple objectives is computationally hard, and most tools rely on heuristics to sample the vast sequence design space. In this review we study some of the algorithmic issues behind gene optimization and the approaches that different tools have adopted to redesign genes and optimize desired coding features. We utilize test cases to demonstrate the efficiency of each approach, as well as identify their strengths and limitations.
The technology industry has fought bitterly over patents and other property rights in recent years. Could the fast-moving changes brought on by new kinds of technology make those fights less important?
"A cell free protein synthesis approach is extensively used for biochemical and synthetic biology researches. Unlike lysate based cell free systems, the PURE system is reconstituted with individually purified factors essential for transcriptional and translational processes. Hence, the components in the PURE system can be definitely manipulated as per the desired situation. Because of this high controllability, the PURE system has been applied to a wide range of research scene, such as biochemical analysis in reconstructed system, in vitro protein engineering, reconstitution of an artificial cell. We believe that this purified cell-free protein synthesis system become a basal technology to advance synthetic biology."
"We describe an algorithm for designing the equilibrium base-pairing properties of a test tube of interacting nucleic acid strands. A target test tube is specified as a set of desired “on-target” complexes, each with a target secondary structure and target concentration, and a set of undesired “off-target” complexes, each with vanishing target concentration. Sequence design is performed by optimizing the test tube ensemble defect, corresponding to the concentration of incorrectly paired nucleotides at equilibrium evaluated over the ensemble of the test tube. To reduce the computational cost of accepting or rejecting mutations to a random initial sequence, the structural ensemble of each on-target complex is hierarchically decomposed into a tree of conditional subensembles, yielding a forest of decomposition trees. Candidate sequences are evaluated efficiently at the leaf level of the decomposition forest by estimating the test tube ensemble defect from conditional physical properties calculated over the leaf subensembles. As optimized subsequences are merged toward the root level of the forest, any emergent defects are eliminated via ensemble redecomposition and sequence reoptimization. After successfully merging subsequences to the root level, the exact test tube ensemble defect is calculated for the first time, explicitly checking for the effect of the previously neglected off-target complexes. Any off-target complexes that form at appreciable concentration are hierarchically decomposed, added to the decomposition forest, and actively destabilized during subsequent forest reoptimization. For target test tubes representative of design challenges in the molecular programming and synthetic biology communities, our test tube design algorithm typically succeeds in achieving a normalized test tube ensemble defect ≤1% at a design cost within an order of magnitude of the cost of test tube analysis."
"Researchers would like to place very small implants deep inside our bodies to monitor health or treat pain. But providing electric power to implants without wires or batteries has been a big obstacle.
Now, engineers are developing a way to send power—safely and wirelessly—to “smart chips” programmed to perform medical tasks and report back the results.
The approach involves beaming ultrasound at a tiny device inside the body designed to do three things: convert the incoming sound waves into electricity, process and execute medical commands, and report the completed activity via a tiny built-in radio antenna.
“We think this will enable researchers to develop a new generation of tiny implants designed for a wide array of medical applications,” says Amin Arbabian, assistant professor of electrical engineering at Stanford University.
Arbabian’s team recently presented a working prototype of this wireless medical implant system at the IEEE Custom Integrated Circuits Conference in San Jose, California.
TINY, WIRELESS NODES
The researchers chose ultrasound to deliver wireless power to their medical implants because it has been safely used in many applications, such as fetal imaging, and can provide sufficient power to implants a millimeter or less in size.
Now, Arbabian and his colleagues are collaborating with other researchers to develop sound-powered implants for a variety of medical applications, including studying the nervous system and treating the symptoms of Parkinson’s disease.
“Tiny, wireless nodes such as these have the potential to become a key tool for addressing neurological disorders,” says Florian Solzbacher, professor of electrical and computer engineering at University of Utah and director of its Center for Engineering Innovation.
POWERED BY PIEZOELECTRICITY
The implant chip is powered by piezoelectricity, which is electricity caused by pressure....."