SynBioFromLeukipposInstitute
115.2K views | +11 today
Follow
 
Scooped by Gerd Moe-Behrens
onto SynBioFromLeukipposInstitute
Scoop.it!

Using photosynthesis to generate fresh water

Using photosynthesis to generate fresh water | SynBioFromLeukipposInstitute | Scoop.it
Annegret Honsbein explains how she plans to harness the power of photosynthesis to desalinate sea water and generate fresh water.
more...
No comment yet.
SynBioFromLeukipposInstitute
Your new post is loading...
Your new post is loading...
Scooped by Gerd Moe-Behrens
Scoop.it!

Biological signalling processes in intelligent materials 

Biological signalling processes in intelligent materials  | SynBioFromLeukipposInstitute | Scoop.it
Researchers are developing innovative biohybrid systems with information processing functionality.
more...
No comment yet.
Scooped by Gerd Moe-Behrens
Scoop.it!

New NSF Awards Support the Creation of Bio-Based Semiconductors

New NSF Awards Support the Creation of Bio-Based Semiconductors | SynBioFromLeukipposInstitute | Scoop.it
July 17, 2018 -- To address a worldwide need for data storage that far outstrips today's capabilities, federal agencies and a technology research...
more...
No comment yet.
Scooped by Gerd Moe-Behrens
Scoop.it!

BREAKING: CRISPR Could Be Causing Extensive Mutations And Genetic Damage After All

BREAKING: CRISPR Could Be Causing Extensive Mutations And Genetic Damage After All | SynBioFromLeukipposInstitute | Scoop.it
CRISPR has been heralded as one of the most important breakthroughs in modern science, but there could be a hidden and potentially dangerous side effect to the wonders of its genetic editing technology, a new study reveals.

A systematic investigation of CRISPR/Cas9 genome editing in mouse and human cells has discovered that the technique appears to frequently cause extensive mutations and genetic damage that the researchers say wouldn't be detected by existing DNA tests.

"This is the first systematic assessment of unexpected events resulting from CRISPR/Cas9 editing in therapeutically relevant cells," explains geneticist Allan Bradley from the Wellcome Sanger Institute in the UK.

"We found that changes in the DNA have been seriously underestimated before now."

It's not the first time scientists have raised alarm about the potential pitfalls of CRISPR.

In May last year, a team from Columbia University made headlines when they announced the genetic editing toolkit could introduce hundreds of off-target mutations to the genome.

Those claims were later retracted when the scientists involved in the original study were unable to replicate their own results, but since then other research has also suggested CRISPR could cause dangerous side effects.

To investigate these kinds of possibilities further, Bradley and fellow researchers examined the effects of the technique on mouse stem cells and human retinal epithelial cells.

"My initial experiment used CRISPR/Cas9 as a tool to study gene activity, however it became clear that something unexpected was happening," says the first author of the new study, PhD student Michael Kosicki.

"Once we realised the extent of the genetic rearrangements we studied it systematically, looking at different genes and different therapeutically relevant cell lines, and showed that the CRISPR/Cas9 effects held true."

Those effects included large deletions or mutations that happened even several thousand DNA bases (aka kilobases) away from the target site where CRISPR/Cas9 was used to make the edit.

Not only could such significant mutations of the DNA code have potentially harmful effects – by disrupting healthy gene and cellular functioning – but the researchers warn that standard DNA genotyping assays may not ordinarily pick up on these mistakes.

In the worst-case scenario, if such mangled edits were introduced into humans in a CRISPR/Cas9 treatment, important genes might end up being switched on or off, which could make for potentially serious health consequences.

"In the clinical context of editing many billions of cells, the multitude of different mutations generated makes it likely that one or more edited cells in each protocol would be endowed with an important pathogenic lesion," the authors write.

"Such lesions may constitute a first carcinogenic 'hit' in stem cells and progenitors, which have a long replicative lifespan and may become neoplastic [promoting abnormal growths] with time."

If such unforeseen side effects can indeed be introduced by using CRISPR/Cas9 to snip at the genome, the researchers say it's imperative for future clinical applications to address the risks.

And it's likely a lot more research will be needed to find out whether it's possible to prevent such editing errors from arising.

"It is important that anyone thinking of using this technology for gene therapy proceeds with caution," Bradley says, "and looks very carefully to check for possible harmful effects."

The findings are reported in Nature Biotechnology.
more...
No comment yet.
Scooped by Gerd Moe-Behrens
Scoop.it!

Perspective: Solidifying the Impact of Cell-Free Synthetic Biology Through Lyophilization 

Cell-free synthetic biology is an exciting and new branch in the field of synthetic biology. Based on in vitro transcription and translation systems, this application-focused domain builds on decades of cell-free biochemistry and protein expression to operate synthetic gene networks outside of cellular environments. This has brought new and perhaps even unexpected advantages. Chief among these is the ability to operate genetically encoded tools in a sterile and abiotic format. Recent work has extended this advantage by freeze-drying these cell-free systems into dried pellets or embedded paper-based reactions. Taken together, these new ideas have solved the longstanding challenge of how to deploy poised synthetic gene networks in a biosafe mode outside of the laboratory. There is significant excitement in the potential of this newfound venue and the community has begun to extend proof-of-concept demonstrations in important and creative ways. Here I explore these new efforts and provide my thoughts on the challenges and opportunities ahead for freeze-dried, cell-free synthetic biology.
more...
No comment yet.
Scooped by Gerd Moe-Behrens
Scoop.it!

Noise control for molecular computing

Synthetic biology is a growing interdisciplinary field, with far-reaching applications, which aims to design biochemical systems that behave in a desired manner. With the advancement in nucleic-acid-based technology in general, and strand-displacement DNA computing in particular, a large class of abstract biochemical networks may be physically realized using nucleic acids. Methods for systematic design of the abstract systems with prescribed behaviours have been predominantly developed at the (less-detailed) deterministic level. However, stochastic effects, neglected at the deterministic level, are increasingly found to play an important role in biochemistry. In such circumstances, methods for controlling the intrinsic noise in the system are necessary for a successful network design at the (more-detailed) stochastic level. To bridge the gap, the noise-control algorithm for designing biochemical networks is developed in this paper. The algorithm structurally modifies any given reaction network under mass-action kinetics, in such a way that (i) controllable state-dependent noise is introduced into the stochastic dynamics, while (ii) the deterministic dynamics are preserved. The capabilities of the algorithm are demonstrated on a production-decay reaction system, and on an exotic system displaying bistability. For the production-decay system, it is shown that the algorithm may be used to redesign the network to achieve noise-induced multistability. For the exotic system, the algorithm is used to redesign the network to control the stochastic switching, and achieve noise-induced oscillations.
more...
No comment yet.
Scooped by Gerd Moe-Behrens
Scoop.it!

Programming self-organizing multicellular structures with synthetic cell-cell signaling

Programming self-organizing multicellular structures with synthetic cell-cell signaling | SynBioFromLeukipposInstitute | Scoop.it
A common theme in the self-organization of multicellular tissues is the use of cell-cell signaling networks to induce morphological changes. We used the modular synNotch juxtacrine signaling platform to engineer artificial genetic programs in which specific cell-cell contacts induced changes in cadherin cell adhesion. Despite their simplicity, these minimal intercellular programs were sufficient to yield assemblies with hallmarks of natural developmental systems: robust self-organization into multidomain structures, well-choreographed sequential assembly, cell type divergence, symmetry breaking, and the capacity for regeneration upon injury. The ability of these networks to drive complex structure formation illustrates the power of interlinking cell signaling with cell sorting: Signal-induced spatial reorganization alters the local signals received by each cell, resulting in iterative cycles of cell fate branching. These results provide insights into the evolution of multicellularity and demonstrate the potential to engineer customized self-organizing tissues or materials.
more...
No comment yet.
Scooped by Gerd Moe-Behrens
Scoop.it!

Frontiers | ‘Do it Yourself’ microbial cultivation techniques for synthetic and systems biology: cheap, fun and flexible | Microbiology

With the emergence of inexpensive 3D printing technology, open-source platforms for electronic prototyping and single-board computers, ‘Do it Yourself’ (DIY) approaches to cultivation of microbial cultures are becoming more feasible, user-friendly and thus wider spread. In this perspective, we survey some of these approaches, as well as add-on solutions to commercial instruments for synthetic and system biology applications. We discuss different cultivation designs, including capabilities and limitations. Our intention is to encourage the reader to consider DIY solutions. Overall, custom cultivation devices offer controlled growth environments with in-line monitoring of, for example, optical density, fluorescence, pH, and dissolved oxygen, all at affordable prices. Moreover, they offer a great degree of flexibility for different applications and requirements and are fun to design and construct. We include several illustrative examples, such as gaining optogenetic control, and adaptive laboratory evolution experiments.
more...
No comment yet.
Scooped by Gerd Moe-Behrens
Scoop.it!

Scientists Invented AI Made From DNA

Scientists Invented AI Made From DNA | SynBioFromLeukipposInstitute | Scoop.it
Researchers made a neural network out of DNA that can recognize handwritten numbers.
more...
No comment yet.
Scooped by Gerd Moe-Behrens
Scoop.it!

Scaling up molecular pattern recognition with DNA-based winner-take-all neural networks

Scaling up molecular pattern recognition with DNA-based winner-take-all neural networks | SynBioFromLeukipposInstitute | Scoop.it
From bacteria following simple chemical gradients1 to the brain distinguishing complex odour information2, the ability to recognize molecular patterns is essential for biological organisms. This type of information-processing function has been implemented using DNA-based neural networks3, but has been limited to the recognition of a set of no more than four patterns, each composed of four distinct DNA molecules. Winner-take-all computation4 has been suggested5,6 as a potential strategy for enhancing the capability of DNA-based neural networks. Compared to the linear-threshold circuits7 and Hopfield networks8 used previously3, winner-take-all circuits are computationally more powerful4, allow simpler molecular implementation and are not constrained by the number of patterns and their complexity, so both a large number of simple patterns and a small number of complex patterns can be recognized. Here we report a systematic implementation of winner-take-all neural networks based on DNA-strand-displacement9,10 reactions. We use a previously developed seesaw DNA gate motif3,11,12, extended to include a simple and robust component that facilitates the cooperative hybridization13 that is involved in the process of selecting a ‘winner’. We show that with this extended seesaw motif DNA-based neural networks can classify patterns into up to nine categories. Each of these patterns consists of 20 distinct DNA molecules chosen from the set of 100 that represents the 100 bits in 10 × 10 patterns, with the 20 DNA molecules selected tracing one of the handwritten digits ‘1’ to ‘9’. The network successfully classified test patterns with up to 30 of the 100 bits flipped relative to the digit patterns ‘remembered’ during training, suggesting that molecular circuits can robustly accomplish the sophisticated task of classifying highly complex and noisy information on the basis of similarity to a memory.
more...
No comment yet.
Scooped by Gerd Moe-Behrens
Scoop.it!

Living Supramolecular Polymerization of DNA

Recently there have been notable synthetic successes in supramolecular polymerization. By contrast, it has long been known that DNA can undergo supramolecular polymerization (concatemerization). Concatemerization is a step-like polymerization and consequently suffers from broad molecular weight distributions and generally undesirable cyclization reactions. Here we demonstrate that another supramolecular polymerization of DNA, hybridization chain reaction (HCR), is in fact a living polymerization. After consumption of initial monomer, the polymerization can be continued with further addition of monomer, and the molecular weight can be varied by the ratio of monomer to initiator. In contrast to concatemerization, HCR produces polymers with narrow dispersity while avoiding cyclization. Identification of the living character of this supramolecular polymerization presents new opportunities in structural DNA nanotechnology and molecular biology.
more...
No comment yet.
Scooped by Gerd Moe-Behrens
Scoop.it!

A biochemical logarithmic sensor with broad dynamic range - F1000Research

Sensory perception often scales logarithmically with the input level. Similarly, the output response of biochemical systems sometimes scales logarithmically with the input signal that drives the system. How biochemical systems achieve logarithmic sensing remains an open puzzle. This article shows how a biochemical logarithmic sensor can be constructed from the most basic principles of chemical reactions. Assuming that reactions follow the classic Michaelis-Menten kinetics of mass action or the more generalized and commonly observed Hill equation response, the summed output of several simple reactions with different sensitivities to the input will often give an aggregate output response that logarithmically transforms the input. The logarithmic response is robust to stochastic fluctuations in parameter values. This model emphasizes the simplicity and robustness by which aggregate chemical circuits composed of sloppy components can achieve precise response characteristics. Both natural and synthetic designs gain from the power of this aggregate approach.
more...
No comment yet.
Scooped by Gerd Moe-Behrens
Scoop.it!

Synthetic Biology of Small RNAs and Riboswitches

Microbiol Spectr. 2018 May;6(3). doi: 10.1128/microbiolspec.RWR-0007-2017.
more...
No comment yet.
Scooped by Gerd Moe-Behrens
Scoop.it!

DNA-ROM: New Grant Aims for Memory Chips Based on DNA

DNA-ROM: New Grant Aims for Memory Chips Based on DNA | SynBioFromLeukipposInstitute | Scoop.it
Josh Hihath is trying to fuse biology and electrical engineering and to build new types of electronic memory based on DNA.Hihath, professor in the UC Davis Department of Electrical and Computer Engineering, is principal investigator of a grant just …Continue reading about DNA-ROM: New Grant Aims ...
more...
No comment yet.
Scooped by Gerd Moe-Behrens
Scoop.it!

Repair of double-strand breaks induced by CRISPR–Cas9 leads to large deletions and complex rearrangements

Repair of double-strand breaks induced by CRISPR–Cas9 leads to large deletions and complex rearrangements | SynBioFromLeukipposInstitute | Scoop.it
CRISPR–Cas9 is poised to become the gene editing tool of choice in clinical contexts. Thus far, exploration of Cas9-induced genetic alterations has been limited to the immediate vicinity of the target site and distal off-target sequences, leading to the conclusion that CRISPR–Cas9 was reasonably specific. Here we report significant on-target mutagenesis, such as large deletions and more complex genomic rearrangements at the targeted sites in mouse embryonic stem cells, mouse hematopoietic progenitors and a human differentiated cell line. Using long-read sequencing and long-range PCR genotyping, we show that DNA breaks introduced by single-guide RNA/Cas9 frequently resolved into deletions extending over many kilobases. Furthermore, lesions distal to the cut site and crossover events were identified. The observed genomic damage in mitotically active cells caused by CRISPR–Cas9 editing may have pathogenic consequences.
more...
No comment yet.
Scooped by Gerd Moe-Behrens
Scoop.it!

An enhanced CRISPR repressor for targeted mammalian gene regulation

An enhanced CRISPR repressor for targeted mammalian gene regulation | SynBioFromLeukipposInstitute | Scoop.it
The fusion of dead Cas9 with KRAB and the transcriptional repressor domain of the chromatin modifier MeCP2 leads to an efficient transcriptional silencer that can be applied to genome-scale screens and genetic circuits.
more...
No comment yet.
Scooped by Gerd Moe-Behrens
Scoop.it!

Xeno Nucleic Acid Nanosensors for Enhanced Stability Against Ion-induced Perturbations

The omnipresence of salts in biofluids creates a pervasive challenge in designing sensors suitable for in vivo applications. Fluctuations in ion concentrations have been shown to affect the sensitivity and selectivity of optical sensors based on single-walled carbon nanotubes wrapped with single-stranded DNA (ssDNA-SWCNTs). We herein observe fluorescence wavelength shifting for ssDNA-SWCNT-based optical sensors in the presence of divalent cations at concentrations above 3.5 mM. In contrast, no shifting was observed for concentrations up to 350 mM for sensors bioengineered with increased rigidity using xeno nucleic acids (XNAs). Transient fluorescence measurements reveal distinct optical transitions for ssDNA- and XNA-based wrappings during ion-induced conformation changes, with XNA-based sensors showing increased permanence in conformational and signal stability. This demonstration introduces synthetic biology as a complementary means for enhancing nanotube optoelectronic behaviour, unlocking previously unexplored possibilities for developing nano-bioengineered sensors with augmented capabilities.
more...
No comment yet.
Scooped by Gerd Moe-Behrens
Scoop.it!

CRISPR screens identify genomic ribonucleotides as a source of PARP-trapping lesions

CRISPR screens identify genomic ribonucleotides as a source of PARP-trapping lesions | SynBioFromLeukipposInstitute | Scoop.it
The observation that BRCA1- and BRCA2-deficient cells are sensitive to inhibitors of poly(ADP–ribose) polymerase (PARP) has spurred the development of cancer therapies that use these inhibitors to target deficiencies in homologous recombination1. The cytotoxicity of PARP inhibitors depends on PARP trapping, the formation of non-covalent protein–DNA adducts composed of inhibited PARP1 bound to DNA lesions of unclear origins1,2,3,4. To address the nature of such lesions and the cellular consequences of PARP trapping, we undertook three CRISPR (clustered regularly interspersed palindromic repeats) screens to identify genes and pathways that mediate cellular resistance to olaparib, a clinically approved PARP inhibitor1. Here we present a high-confidence set of 73 genes, which when mutated cause increased sensitivity to PARP inhibitors. In addition to an expected enrichment for genes related to homologous recombination, we discovered that mutations in all three genes encoding ribonuclease H2 sensitized cells to PARP inhibition. We establish that the underlying cause of the PARP-inhibitor hypersensitivity of cells deficient in ribonuclease H2 is impaired ribonucleotide excision repair5. Embedded ribonucleotides, which are abundant in the genome of cells deficient in ribonucleotide excision repair, are substrates for cleavage by topoisomerase 1, resulting in PARP-trapping lesions that impede DNA replication and endanger genome integrity. We conclude that genomic ribonucleotides are a hitherto unappreciated source of PARP-trapping DNA lesions, and that the frequent deletion of RNASEH2B in metastatic prostate cancer and chronic lymphocytic leukaemia could provide an opportunity to exploit these findings therapeutically.
more...
No comment yet.
Scooped by Gerd Moe-Behrens
Scoop.it!

Biochemists discover cause of genome editing failures with hyped CRISPR system

Biochemists discover cause of genome editing failures with hyped CRISPR system | SynBioFromLeukipposInstitute | Scoop.it
Researchers from the University of Illinois at Chicago are the first to describe why CRISPR gene editing sometimes fails to work, and how the process can be made to be much more efficient.
CRISPR is a gene-editing tool that allows scientists to cut out unwanted genes or genetic material from DNA, and sometimes add a desired sequence or genes. CRISPR uses an enzyme called Cas9 that acts like scissors to cut out unwanted DNA. Once cuts are made on either side of the DNA to be removed, the cell either initiates repair to glue the two ends of the DNA strand back together, or the cell dies.
In a study published in the journal Molecular Cell, the researchers showed that when gene editing using CRISPR fails, which occurs about 15 percent of the time, it is often due to persistent binding of the Cas9 protein to the DNA at the cut site, which blocks the DNA repair enzymes from accessing the cut.
Senior author Bradley Merrill, associate professor of biochemistry and molecular genetics in the UIC College of Medicine, says that before now, researchers did not know why the process randomly failed.
"We found that at sites where Cas9 was a 'dud' it stayed bound to the DNA strand and prevented the cell from initiating the repair process," Merrill said. The stuck Cas9 is also unable to go on to make additional cuts in DNA, thus limiting the efficiency of CRISPR, he said.
Merrill, UIC graduate student Ryan Clarke, and their colleagues also found that Cas9 was likely to be ineffective at sites in the genome where RNA polymerases—enzymes involved in gene activity—were not active. Further investigation revealed that guiding Cas9 to anneal to just one of the strands making up the DNA double helix promoted interaction between Cas9 and the RNA polymerase, helping to transform a "dud" Cas9 into an efficient genome editor.
Specifically, they found that consistent strand selection for Cas9 during genome editing forced the RNA polymerases to collide with Cas9 in such a way that Cas9 was knocked off the DNA.
"I was shocked that simply choosing one DNA strand over the other had such a powerful effect on genome editing," said Clarke, the lead author of the paper. "Uncovering the mechanism behind this phenomenon helps us better understand how Cas9 interactions with the genome can cause some editing attempts to fail and that, when designing a genome editing experiment, we can use that understanding to our benefit."
"This new understanding is important for those of us who need genome editing to work well in the lab and for making genome editing more efficient and safer in future clinical uses," Merrill said.
The study findings are also significant because, in the genome editing process, the interaction between Cas9 and the DNA strand is now known to be the "rate-limiting step," said Merrill. This means that it is the slowest part of the process; therefore, changes at this stage have the most potential to impact the overall duration of genome editing.
"If we can reduce the time that Cas9 interacts with the DNA strand, which we now know how to do with an RNA polymerase, we can use less of the enzyme and limit exposure," Merrill said. "This means we have more potential to limit adverse effects or side effects, which is vital for future therapies that may impact human patients."
Explore further: Genome-editing tool could increase cancer risk
More information: Ryan Clarke et al, Enhanced Bacterial Immunity and Mammalian Genome Editing via RNA-Polymerase-Mediated Dislodging of Cas9 from Double-Strand DNA Breaks, Molecular Cell (2018). DOI: 10.1016/j.molcel.2018.06.005
more...
No comment yet.
Scooped by Gerd Moe-Behrens
Scoop.it!

Cafe Synthetique: Open Source Innovations in SynBio

Cafe Synthetique: Open Source Innovations in SynBio | SynBioFromLeukipposInstitute | Scoop.it
This month, we'll be hearing talks by Stephanie Höhn (DAMTP) about her work on open source light sheet microscopy and Hadrien Peyret (John Innes Centre, Norwich) who is designing an open access plant...
more...
No comment yet.
Scooped by Gerd Moe-Behrens
Scoop.it!

Open Source Hardware towards designing for local needs in Tanzania — Synthetic Biology in Cambridge

Eng. Valerian Linus Sanga and Paul Thomas Nyakyi are co-founders of STICLab, a maker space in Dar es Salaam, Tanzania. During this talk, they will explain how maker spaces like STICLab and open source hardware can be leveraged to help tackle local problems around his community.
more...
No comment yet.
Scooped by Gerd Moe-Behrens
Scoop.it!

Self-organizing multicellular structures designed using synthetic biology

Self-organizing multicellular structures designed using synthetic biology | SynBioFromLeukipposInstitute | Scoop.it
Synthetic genetic circuits can induce cells to form simple 3D structures reminiscent of those generated during early embryonic development. This advance will help engineers build tissues that have desirable structures.
more...
No comment yet.
Scooped by Gerd Moe-Behrens
Scoop.it!

Mutually orthogonal DNA replication systems in vivo

The yeast cytoplasmically-localized pGKL1/TP-DNAP1 plasmid/DNA polymerase pair forms an orthogonal DNA replication system whose mutation rate can be drastically increased without influencing genomic replication, thereby supporting in vivo continuous evolution. Here, we report that the pGKL2/TP-DNAP2 plasmid/DNA polymerase pair forms a second orthogonal replication system. We show that custom genes can be encoded and expressed from pGKL2 in a straightforward manner, that error-prone TP-DNAP2s can be engineered, and that pGKL2 replication by TP-DNAP2 is both orthogonal to genomic replication in Saccharomyces cerevisiae and mutually orthogonal with pGKL1 replication by TP-DNAP1. This demonstration of two mutually orthogonal DNA replication systems with tunable error rates and properties should enable new applications in cell-based continuous evolution, genetic recording, and synthetic biology at large.
more...
No comment yet.
Scooped by Gerd Moe-Behrens
Scoop.it!

A biochemical logarithmic sensor with broad dynamic range

Sensory perception often scales logarithmically with the input level. Similarly, the output response of biochemical systems sometimes scales logarithmically with the input signal that drives the system. How biochemical systems achieve logarithmic sensing remains an open puzzle. This article shows how a biochemical logarithmic sensor can be constructed from the most basic principles of chemical reactions. Assuming that reactions follow the classic Michaelis-Menton kinetics of mass action or the more generalized and commonly observed Hill equation response, the summed output of several simple reactions with different sensitivities to the input will often give an aggregate output response that logarithmically transforms the input. The logarithmic response is robust to stochastic fluctuations in parameter values. This model emphasizes the simplicity and robustness by which aggregate chemical circuits composed of sloppy components can achieve precise response characteristics. Both natural and synthetic designs gain from the power of this aggregate approach.
more...
No comment yet.
Scooped by Gerd Moe-Behrens
Scoop.it!

Stochastic Turing patterns in a synthetic bacterial population

The origin of biological morphology and form is one of the deepest problems in science, underlying our understanding of development and the functioning of living systems. In 1952, Alan Turing showed that chemical morphogenesis could arise from a linear instability of a spatially uniform state, giving rise to periodic pattern formation in reaction–diffusion systems but only those with a rapidly diffusing inhibitor and a slowly diffusing activator. These conditions are disappointingly hard to achieve in nature, and the role of Turing instabilities in biological pattern formation has been called into question. Recently, the theory was extended to include noisy activator–inhibitor birth and death processes. Surprisingly, this stochastic Turing theory predicts the existence of patterns over a wide range of parameters, in particular with no severe requirement on the ratio of activator–inhibitor diffusion coefficients. To explore whether this mechanism is viable in practice, we have genetically engineered a synthetic bacterial population in which the signaling molecules form a stochastic activator–inhibitor system. The synthetic pattern-forming gene circuit destabilizes an initially homogenous lawn of genetically engineered bacteria, producing disordered patterns with tunable features on a spatial scale much larger than that of a single cell. Spatial correlations of the experimental patterns agree quantitatively with the signature predicted by theory. These results show that Turing-type pattern-forming mechanisms, if driven by stochasticity, can potentially underlie a broad range of biological patterns. These findings provide the groundwork for a unified picture of biological morphogenesis, arising from a combination of stochastic gene expression and dynamical instabilities.
more...
No comment yet.