Publications by authors named "Susan J Rosser"

In the past decade, there has been substantive progress in gene therapy across disease indications. However, despite multiple gene therapies being approved for clinical use, none have a cardiovascular indication. Several reasons for this have inhibited or delayed progress in the cardiovascular field.

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Lack of standardization in biofoundries limits the scalability and efficiency of synthetic biology research. Here, we propose an abstraction hierarchy that organizes biofoundry activities into four interoperable levels: Project, Service/Capability, Workflow, and Unit Operation, effectively streamlining the Design‑Build‑Test‑Learn (DBTL) cycle. This framework enables more modular, flexible, and automated experimental workflows.

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Super-resolution microscopy has revolutionized biological imaging, enabling the visualization of structures at the nanometer length scale. Its application in live cells, however, has remained challenging. To address this, we adapted LIVE-PAINT, an approach we established in yeast, for application in live mammalian cells.

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CRISPR activation provides an invaluable tool for experimental biologists to convert correlations into causation by directly observing phenotypic changes upon targeted changes in gene expression. With few exceptions, most diseases are caused by complex polygenic interactions, with multiple genes contributing to define the output of a gene network. As such researchers are increasingly interested in tools that can offer not only control but also the capacity to simultaneously upregulate multiple genes.

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Fluorescence microscopy enables specific visualization of proteins in living cells and has played an important role in our understanding of the protein subcellular location and function. Some proteins, however, show altered localization or function when labeled using direct fusions to fluorescent proteins, making them difficult to study in live cells. Additionally, the resolution of fluorescence microscopy is limited to ∼200 nm, which is 2 orders of magnitude larger than the size of most proteins.

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Escin is a mixture of over 30 glycosylated triterpenoid (saponin) structures, extracted from the dried fruit of horse chestnuts. Escin is currently used as an anti-inflammatory, and has potential applications in the treatment of arthritis and cancer. Engineered yeast would enable production of specific bioactive components of escin at industrial scale, however many saponins have been shown to be toxic to yeast.

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We present direct-LIVE-PAINT, an easy-to-implement approach for the nanoscopic imaging of protein structures in live cells using labeled binding peptides. We demonstrate the feasibility of direct-LIVE-PAINT with an actin-binding peptide fused to EGFP, the location of which can be accurately determined as it transiently binds to actin filaments. We show that direct-LIVE-PAINT can be used to image actin structures below the diffraction-limit of light and have used it to observe the dynamic nature of actin in live cells.

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To elucidate principles operating in native biological systems and to develop novel biotechnologies, synthetic biology aims to build and integrate synthetic gene circuits within native transcriptional networks. The utility of synthetic gene circuits for cell engineering relies on the ability to control the expression of all constituent transgene components. Transgene silencing, defined as the loss of expression over time, persists as an obstacle for engineering primary cells and stem cells with transgenic cargos.

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Thanks to its sophistication, the CRISPR/Cas system has been a widely used yeast genome editing method. However, CRISPR methods generally rely on preassembled DNAs and extra cloning steps to deliver gRNA, Cas protein, and donor DNA. These laborious steps might hinder its usefulness.

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The adoption of CRISPR systems for the generation of synthetic transcription factors has greatly simplified the process for upregulating endogenous gene expression, with a plethora of applications in cell biology, bioproduction and cell reprogramming. The recently discovered CRISPR/Cas12a (Cas12a) systems offer extended potential, as Cas12a is capable of processing its own crRNA array, to provide multiple individual crRNAs for subsequent targeting from a single transcript. Here we show the application of dFnCas12a-VPR in mammalian cells, with the Francisella novicida Cas12a (FnCas12a) possessing a shorter PAM sequence than Acidaminococcus sp.

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CRISPR-enabled deaminase base editing has become a powerful tool for precisely editing nucleotides on the chromosome. In this study DNA helicases, such as Escherichia coli DnaB, were fused to activation-induced cytidine deaminase (AID) to form enzyme complexes which randomly introduces edited bases throughout the chromosome. DnaB-AID was found to increase 2.

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Fed-batch cultures of Chinese Hamster Ovary cells have been used to produce high quantities of biotherapeutics, particularly monoclonal antibodies. However, a growing number of next-generation biotherapeutics, such as bi-specific antibodies and fusion proteins, are difficult to express using standard fed-batch processes. Decoupling cell growth and biotherapeutic production is becoming an increasingly desired strategy for the biomanufacturing industry, especially for difficult-to-express products.

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The structure and diversity of all open microbial communities are shaped by individual births, deaths, speciation and immigration events; the precise timings of these events are unknowable and unpredictable. This randomness is manifest as ecological drift in the population dynamics, the importance of which has been a source of debate for decades. There are theoretical reasons to suppose that drift would be imperceptible in large microbial communities, but this is at odds with circumstantial evidence that effects can be seen even in huge, complex communities.

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"Crossing Kingdoms" is an artist-led experiment in the biological fusion of mammalian and yeast cells and the cultural discussions of these phenomena. We present this collaboration as an experiment in responsible research and innovation (RRI), an institutionalized format for ensuring that researchers reflect on the wider social dimensions of their work. Our methods challenged us as researchers to reflect on interdisciplinary collaboration and the possibility of innovating in biology for artistic purposes, challenged audiences to reflect on biological boundaries, and challenged both groups to reflect on what it means to be responsible in science.

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Current base editors (BEs) catalyze only base transitions (C to T and A to G) and cannot produce base transversions. Here we present BEs that cause C-to-A transversions in Escherichia coli and C-to-G transversions in mammalian cells. These glycosylase base editors (GBEs) consist of a Cas9 nickase, a cytidine deaminase and a uracil-DNA glycosylase (Ung).

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Base editing technology based on clustered regularly interspaced short palindromic repeats/associated protein 9 (CRISPR/Cas9) is a recent addition to the family of CRISPR technologies. Compared with the traditional CRISPR/Cas9 technology, it does not rely on DNA double strand break and homologous recombination, and can realize gene inactivation and point mutation more quickly and simply. Herein, we first developed a base editing method for genome editing in utilizing CRISPR/dCas9 (a fully nuclease-deficient mutant of Cas9 from ) and activation-induced cytidine deaminase (AID).

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Triterpenoids are high-value plant metabolites with numerous applications in medicine, agriculture, food, and home and personal care products. However, plants produce triterpenoids in low abundance, and their complex structures make their chemical synthesis prohibitively expensive and often impossible. As such, the yeast Saccharomyces cerevisiae has been explored as an alternative means of production.

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The CRISPR-Cas9 system has become increasingly popular for genome engineering across all fields of biological research, including in the Gram-positive model organism Bacillus subtilis. A major drawback for the commercial use of Cas9 is the IP landscape requiring a license for its use, as well as reach-through royalties on the final product. Recently an alternative CRISPR nuclease, free to use for industrial R&D, MAD7 was released by Inscripta (CO).

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Selectively fluorinated compounds are found frequently in pharmaceutical and agrochemical products where currently 25-30 % of optimised compounds emerge from development containing at least one fluorine atom. There are many methods for the site-specific introduction of fluorine, but all are chemical and they often use environmentally challenging reagents. Biochemical processes for C-F bond formation are attractive, but they are extremely rare.

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Yeast strains have been used extensively as robust microbial cell factories for the production of bulk and fine chemicals, including biofuels (bioethanol), complex pharmaceuticals (antimalarial drug artemisinin and opioid pain killers), flavours, and fragrances (vanillin, nootkatone, and resveratrol). In many cases, it is of benefit to suppress or modify ergosterol biosynthesis during strain engineering, for example, to increase thermotolerance or to increase metabolic flux through an alternate pathway. However, the impact of modifying ergosterol biosynthesis on engineered strains is discussed sparsely in literature, and little attention has been paid to the implications of these modifications on the general health and well-being of yeast.

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Serine integrases are emerging as core tools in synthetic biology and have applications in biotechnology and genome engineering. We have designed a split-intein serine integrase-based system with potential for regulation of site-specific recombination events at the protein level in vivo. The ϕC31 integrase was split into two extein domains, and intein sequences (Npu DnaEN and Ssp DnaEC) were attached to the two termini to be fused.

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The original version of this Comment contained errors in the legend of Figure 2, in which the locations of the fifteenth and sixteenth GBA members were incorrectly given as '(15) Australian Genome Foundry, Macquarie University; (16) Australian Foundry for Advanced Biomanufacturing, University of Queensland.'. The correct version replaces this with '(15) Australian Foundry for Advanced Biomanufacturing (AusFAB), University of Queensland and (16) Australian Genome Foundry, Macquarie University'.

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Article Synopsis
  • Biofoundries offer a combined system for quickly designing, building, and testing genetically modified organisms for biotech research and applications.
  • Numerous biofoundries are being developed around the world.
  • A Global Biofoundry Alliance has been created to align and coordinate efforts among these facilities globally.
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A device that counts and records the number of events experienced by an individual cell could have many uses in experimental biology and biotechnology. Here, we report a DNA-based 'latch' that switches between two states upon each exposure to a repeated stimulus. The key component of the latch is a DNA segment whose orientation is inverted by the actions of ϕC31 integrase and its recombination directionality factor (RDF).

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