bims-mricoa Biomed News
on MRI contrast agents
Issue of 2022‒07‒10
three papers selected by
Merve Yavuz
Bilkent University

  1. Curr Opin Microbiol. 2022 Jul 04. pii: S1369-5274(22)00058-3. [Epub ahead of print]69 102174
      Light-driven carbon fixation is a promising option for reducing carbon emissions and alleviating the energy crisis. However, light energy conversion is a major limitation for supporting efficient downstream CO2 fixation pathways. Based on biomimetic technology and synthetic biology, we elaborate on new light-driven technologies in engineered bacteria from three aspects: light energy capture, reducing power generation, and energy generation. In this review, we focus on the current progress in light-driven carbon fixation and discuss new methods with great potential for industrial bioproduction, providing guidance for the development and improvement of bacterial light-driven platforms to convert CO2 into value-added chemicals.
  2. Front Oncol. 2022 ;12 867271
      Siderophores are iron chelating molecules produced by nearly all organisms, most notably by bacteria, to efficiently sequester the limited iron that is available in the environment. Siderophores are an essential component of mammalian iron homeostasis and the ongoing interspecies competition for iron. Bacteria produce a broad repertoire of siderophores with a canonical role in iron chelation and the capacity to perform versatile functions such as interacting with other microbes and the host immune system. Siderophores are a vast area of untapped potential in the field of cancer research because cancer cells demand increased iron concentrations to sustain rapid proliferation. Studies investigating siderophores as therapeutics in cancer generally focused on the role of a few siderophores as iron chelators; however, these studies are limited and some show conflicting results. Moreover, siderophores are biologically conserved, structurally diverse molecules that perform additional functions related to iron chelation. Siderophores also have a role in inflammation due to their iron acquisition and chelation properties. These diverse functions may contribute to both risks and benefits as therapeutic agents in cancer. The potential of siderophore-mediated iron and bacterial modulation to be used in the treatment of cancer warrants further investigation. This review discusses the wide range of bacterial siderophore functions and their utilization in cancer treatment to further expand their functional relevance in cancer detection and treatment.
    Keywords:  bacteria; cancer; deferoxamine; enterobactin; iron; microbiome; siderophores; tumor
  3. Nat Commun. 2022 Jul 07. 13(1): 3908
      Plasmids are one of the most commonly used platforms for genetic engineering and recombinant gene expression in bacteria. The range of available copy numbers for cloning vectors is largely restricted to the handful of Origins of Replication (ORIs) that have been isolated from plasmids found in nature. Here, we introduce two systems that allow for the continuous, finely-tuned control of plasmid copy number between 1 and 800 copies per cell: a plasmid with an anhydrotetracycline-controlled copy number, and a parallelized assay that is used to generate a continuous spectrum of 1194 ColE1-based copy number variants. Using these systems, we investigate the effects of plasmid copy number on cellular growth rates, gene expression, biosynthesis, and genetic circuit performance. We perform single-cell timelapse measurements to characterize plasmid loss, runaway plasmid replication, and quantify the impact of plasmid copy number on the variability of gene expression. Using our assay, we find that each plasmid imposes a 0.063% linear metabolic burden on their hosts, hinting at a simple relationship between metabolic burdens and plasmid DNA synthesis. Our systems enable the precise control of gene expression, and our results highlight the importance of tuning plasmid copy number as a powerful tool for the optimization of synthetic biological systems.