scholarly journals Hybrid Living Capsules Autonomously Produced by Engineered Bacteria

2020 ◽  
Author(s):  
Daniel P. Birnbaum ◽  
Avinash Manjula-Basavanna ◽  
Anton Kan ◽  
Neel S. Joshi
Keyword(s):  
Bacterial Culture ◽  
Enzymatic Catalysis ◽  
Acetic Acid Bacterium ◽  
Simple Approach ◽  
Model Organisms ◽  
Gluconacetobacter Hansenii ◽  
E Coli ◽  
Rich Media ◽  
Matrix Yielding ◽  
Engineered Bacteria

AbstractBacterial cellulose (BC) has excellent material properties and can be produced cheaply and sustainably through simple bacterial culture, but BC-producing bacteria lack the extensive genetic toolkits of model organisms such as Escherichia coli. Here, we describe a simple approach for producing highly programmable BC materials through incorporation of engineered E. coli. The acetic acid bacterium Gluconacetobacter hansenii was co-cultured with engineered E. coli in droplets of glucose-rich media to produce robust cellulose capsules, which were then colonized by the E. coli upon transfer to selective lysogeny broth media. We show that the encapsulated E. coli can produce engineered protein nanofibers within the cellulose matrix, yielding hybrid capsules capable of sequestering specific biomolecules from the environment and enzymatic catalysis. Furthermore, we produced capsules capable of altering their own bulk physical properties through enzyme-induced biomineralization. This novel system, based on autonomous biological fabrication, significantly expands the functionality of BC-based living materials.

scholarly journals Metabolome and proteome analyses reveal transcriptional misregulation in glycolysis of engineered E. coli

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Chun-Ying Wang ◽  
Martin Lempp ◽  
Niklas Farke ◽  
Stefano Donati ◽  
Timo Glatter ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Binding Site ◽  
Metabolic Pathways ◽  
Glycerol Production ◽  
Inducible Promoters ◽  
E Coli ◽  
Inhibition Of Glycolysis ◽  
Underlying Mechanisms ◽  
Rate Limiting ◽  
Engineered Bacteria

AbstractSynthetic metabolic pathways are a burden for engineered bacteria, but the underlying mechanisms often remain elusive. Here we show that the misregulated activity of the transcription factor Cra is responsible for the growth burden of glycerol overproducing E. coli. Glycerol production decreases the concentration of fructose-1,6-bisphoshate (FBP), which then activates Cra resulting in the downregulation of glycolytic enzymes and upregulation of gluconeogenesis enzymes. Because cells grow on glucose, the improper activation of gluconeogenesis and the concomitant inhibition of glycolysis likely impairs growth at higher induction of the glycerol pathway. We solve this misregulation by engineering a Cra-binding site in the promoter controlling the expression of the rate limiting enzyme of the glycerol pathway to maintain FBP levels sufficiently high. We show the broad applicability of this approach by engineering Cra-dependent regulation into a set of constitutive and inducible promoters, and use one of them to overproduce carotenoids in E. coli.

scholarly journals Bacterial enteritis in an oriental white backed vulture (Gyps bengalensis) and its successful management

2012 ◽  
Vol 2 (1) ◽  
pp. 1 ◽  
Author(s):  
Vijay Kumar ◽  
Prasenjit Dhar ◽  
Mandeep Sharma ◽  
Anshu Raj
Keyword(s):  
Bacterial Culture ◽  
Oral Rehydration Solution ◽  
Successful Management ◽  
Oral Rehydration ◽  
E Coli ◽  
Rehydration Solution ◽  
Gyps Bengalensis

An oriental white backed vulture weighing about 8 kg was rescued from a farmer’s field in a moribund condition. The vulture was showing signs of drooping feathers and wings, anorexia, unable to stand, and severe enteritis with dehydration. Bacterial culture from the cloaca of the bird revealed association of hemolytic E. coli that was sensitive to enrofloxacin and ciprofloxacin. The bird was treated successfully with injectable enrofloxacin and oral rehydration solution. No parasitic eggs/protozoal oocysts or hemoprotozoan parasites could be detected in the bird. The bird recovered uneventfully and started taking feed and water normally.

The construction of an engineered bacterium to remove cadmium from wastewater

2014 ◽  
Vol 70 (12) ◽  
pp. 2015-2021 ◽  
Author(s):  
S. Chang ◽  
H. Shu
Keyword(s):  
Phytochelatin Synthase ◽  
Serine Acetyltransferase ◽  
Cd Accumulation ◽  
Glutathione Synthesis ◽  
E Coli ◽  
Limiting Step ◽  
Atpase Gene ◽  
Key Genes ◽  
Engineered Bacteria ◽  
Heavy Metal Atpase

The removal of cadmium (Cd) from wastewater before it is released from factories is important for protecting human health. Although some researchers have developed engineered bacteria, the resistance of these engineered bacteria to Cd have not been improved. In this study, two key genes involved in glutathione synthesis (gshA and gshB), a serine acetyltransferase gene (cysE), a Thlaspi caerulescens phytochelatin synthase gene (TcPCS1), and a heavy metal ATPase gene (TcHMA3) were transformed into Escherichia coli BL21. The resistance of the engineered bacterium to Cd was significantly greater than that of the initial bacterium and the Cd accumulation in the engineered bacterium was much higher than in the initial bacterium. In addition, the Cd resistance of the bacteria harboring gshB, gshA, cysE, and TcPCS1 was higher than that of the bacteria harboring gshA, cysE, and TcPCS1. This finding demonstrated that gshB played an important role in glutathione synthesis and that the reaction catalyzed by glutathione synthase was the limiting step for producing phytochelatins. Furthermore, TcPCS1 had a greater specificity and a higher capacity for removing Cd than SpPCS1, and TcHMA3 not only played a role in T. caerulescens but also functioned in E. coli.

scholarly journals Transcriptional regulation in model organisms: recent progress and clinical implications

Open Biology ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 190183 ◽  
Author(s):  
Jiaqi Tang ◽  
Zhenhua Xu ◽  
Lianfang Huang ◽  
Hui Luo ◽  
Xiao Zhu
Keyword(s):  
Transcriptional Regulation ◽  
Molecular Mechanisms ◽  
The Body ◽  
Model Organisms ◽  
Clinical Implications ◽  
Regulation Mechanism ◽  
Biological Behaviour ◽  
E Coli ◽  
Different Types

In this review, we will summarize model organisms used by scientists in the laboratory, including Escherichia coli , yeast, Arabidopsis thaliana , nematodes, Drosophila , zebrafish, mice and other animals. We focus on the progress in research exploring different types of E. coli in the human body, and the specific molecular mechanisms by which they play a role in humans. First, we discuss the specific transcriptional regulation mechanism of E. coli in cell development, maturation, ageing and longevity, as well as tumorigenesis and development. Then, we discuss how the synthesis of some important substances in cells is regulated and how this affects biological behaviour. Understanding and applying these mechanisms, presumably, can greatly improve the quality of people's lives as well as increase their lifespan. For example, some E. coli can activate certain cells by secreting insulin-like growth factor-1, thus activating the inflammatory response of the body, while other E. coli can inactivate the immune response of the body by secreting toxic factors.

scholarly journals Adhesion ofE. coliBacteria Cells to Prosthodontic Alloys Surfaces Modified by TiO2Sol-Gel Coatings

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Katarzyna Banaszek ◽  
Witold Szymanski ◽  
Bożena Pietrzyk ◽  
Leszek Klimek
Keyword(s):  
Titanium Dioxide ◽  
Bacterial Adhesion ◽  
Culture Medium ◽  
Bacterial Culture ◽  
Bare Metal ◽  
Bacterial Cells ◽  
E Coli ◽  
Modified Surfaces ◽  
Bare Substrate ◽  
Scanning Electron

The evaluation of the degree of bacteriaE. coliadhesion to modified surfaces of the chosen prosthodontic alloys was presented. The study was carried out on Co-Cr (Wironit), Ni-Cr (Fantocer), and Fe-Cr-Ni (Magnum AN) alloys. Bare substrate as a control and titanium dioxide coated samples were used. The samples were placed for 24 hours in bacterial culture medium. After incubation period, a number of bacterial cells were evaluated by scanning electron microscope. The study revealed that modification of the alloy surfaces by titanium dioxide coating significantly decreases the amount of bacteria adhering to the surfaces and that additionally bare metal alloy substrates have a different degree of susceptibility to bacterial adhesion.

scholarly journals Encrypting messages with artificial bacterial receptors

2020 ◽  
Vol 16 ◽  
pp. 2749-2756
Author(s):  
Pragati Kishore Prasad ◽  
Naama Lahav-Mankovski ◽  
Leila Motiei ◽  
David Margulies
Keyword(s):  
Protein C ◽  
Molecular Level ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Potential Contribution ◽  
Information Protection ◽  
Emission Pattern ◽  
E Coli ◽  
Artificial Receptors ◽  
Engineered Bacteria

A method for encrypting messages using engineered bacteria and different fluorescently labeled synthetic receptors is described. We show that the binding of DNA-based artificial receptors to E. coli expressing His-tagged outer membrane protein C (His-OmpC) induces a Förster resonance energy transfer (FRET) between the dyes, which results in the generation of a unique fluorescence fingerprint. Because the bacteria continuously divide, the emission pattern generated by the modified bacteria dynamically changes, enabling the system to produce encryption keys that change with time. Thus, this development indicates the potential contribution of live-cell-based encryption systems to the emerging area of information protection at the molecular level.

scholarly journals Cation Transport in Escherichia coli

1961 ◽  
Vol 45 (2) ◽  
pp. 355-369 ◽  
Author(s):  
Stanley G. Schultz ◽  
A. K. Solomon
Keyword(s):  
Growth Medium ◽  
Bacterial Culture ◽  
Coli Strain ◽  
Metabolic Energy ◽  
Logarithmic Phase ◽  
Concentration Gradients ◽  
E Coli ◽  
Ion Movements ◽  
K Concentration ◽  
K 12

Methods have been developed to study the intracellular Na and K concentrations in E. coli, strain K-12. These intracellular cation concentrations have been shown to be functions of the extracellular cation concentrations and the age of the bacterial culture. During the early logarithmic phase of growth, the intracellular K concentration greatly exceeds that of the external medium, whereas the intracellular Na concentration is lower than that of the growth medium. As the age of the culture increases, the intracellular K concentration falls and the intracellular Na concentration rises, changes which are related to the fall in the pH of the medium and to the accumulation of the products of bacterial metabolism. When stationary phase cells, which are rich in Na and poor in K, are resuspended in fresh growth medium, there is a rapid reaccumulation of K and extrusion of Na. These processes represent oppositely directed net ion movements against concentration gradients, and have been shown to be dependent upon the presence of an intact metabolic energy supply.

scholarly journals Novel Translation Initiation Regulation Mechanism in Escherichia coli ptrB Mediated by a 5′-Terminal AUG

2017 ◽  
Vol 199 (14) ◽  
Author(s):  
Heather J. Beck ◽  
Gary R. Janssen
Keyword(s):  
Escherichia Coli ◽  
Translation Initiation ◽  
Translational Regulation ◽  
Current Knowledge ◽  
Upstream Open Reading Frame ◽  
Model Organisms ◽  
Regulation Mechanism ◽  
Rna Regulation ◽  
Content Type ◽  
E Coli

ABSTRACT Alternative translation initiation mechanisms, distinct from the Shine-Dalgarno (SD) sequence-dependent mechanism, are more prevalent in bacteria than once anticipated. Translation of Escherichia coli ptrB instead requires an AUG triplet at the 5′ terminus of its mRNA. The 5′-terminal AUG (5′-uAUG) acts as a ribosomal recognition signal to attract ribosomes to the ptrB mRNA rather than functioning as an initiation codon to support translation of an upstream open reading frame. ptrB expression exhibits a stronger dependence on the 5′-uAUG than the predicted SD sequence; however, strengthening the predicted ptrB SD sequence relieves the necessity for the 5′-uAUG. Additional sequences within the ptrB 5′ untranslated region (5′-UTR) work cumulatively with the 5′-uAUG to control expression of the downstream ptrB coding sequence (CDS), thereby compensating for the weak SD sequence. Replacement of 5′-UTRs from other mRNAs with the ptrB 5′-UTR sequence showed a similar dependence on the 5′-uAUG for CDS expression, suggesting that the regulatory features contained within the ptrB 5′-UTR are sufficient to control the expression of other E. coli CDSs. Demonstration that the 5′-uAUG present on the ptrB leader mRNA is involved in ribosome binding and expression of the downstream ptrB CDS revealed a novel form of translational regulation. Due to the abundance of AUG triplets at the 5′ termini of E. coli mRNAs and the ability of ptrB 5′-UTR regulation to function independently of gene context, the regulatory effects of 5′-uAUGs on downstream CDSs may be widespread throughout the E. coli genome. IMPORTANCE As the field of synthetic biology continues to grow, a complete understanding of basic biological principles will be necessary. The increasing complexity of the synthetic systems highlights the gaps in our current knowledge of RNA regulation. This study demonstrates that there are novel ways to regulate canonical Shine-Dalgarno-led mRNAs in Escherichia coli, illustrating that our understanding of the fundamental processes of translation and RNA regulation is still incomplete. Even for E. coli, one of the most-studied model organisms, genes with translation initiation mechanisms that do not fit the canonical Shine-Dalgarno sequence paradigm are being revealed. Uncovering diverse mechanisms that control translational expression will allow synthetic biologists to finely tune protein production of desired gene products.

scholarly journals The Antimicrobial Mechanism of Action of Epsilon-Poly-l-Lysine

2014 ◽  
Vol 80 (24) ◽  
pp. 7758-7770 ◽  
Author(s):  
Morten Hyldgaard ◽  
Tina Mygind ◽  
Brian S. Vad ◽  
Marcel Stenvang ◽  
Daniel E. Otzen ◽  
...  
Keyword(s):  
Lipid Bilayers ◽  
Mechanism Of Action ◽  
Cell Morphology ◽  
Morphological Changes ◽  
Divalent Cations ◽  
Membrane Integrity ◽  
Model Organisms ◽  
Microscopy Imaging ◽  
Content Type ◽  
E Coli

ABSTRACTEpsilon-poly-l-lysine (ε-PL) is a natural antimicrobial cationic peptide which is generally regarded as safe (GRAS) as a food preservative. Although its antimicrobial activity is well documented, its mechanism of action is only vaguely described. The aim of this study was to clarify ε-PL's mechanism of action usingEscherichia coliandListeria innocuaas model organisms. We examined ε-PL's effect on cell morphology and membrane integrity and used an array ofE. colideletion mutants to study how specific outer membrane components affected the action of ε-PL. We furthermore studied its interaction with lipid bilayers using membrane models.In vitrocell studies indicated that divalent cations and the heptose I and II phosphate groups in the lipopolysaccharide layer ofE. coliare critical for ε-PL's binding efficiency. ε-PL removed the lipopolysaccharide layer and affected cell morphology ofE. coli, whileL. innocuaunderwent minor morphological changes. Propidium iodide staining showed that ε-PL permeabilized the cytoplasmic membrane in both species, indicating the membrane as the site of attack. We compared the interaction with neutral or negatively charged membrane systems and showed that the interaction with ε-PL relied on negative charges on the membrane. Suspended membrane vesicles were disrupted by ε-PL, and a detergent-like disruption ofE. colimembrane was confirmed by atomic force microscopy imaging of supported lipid bilayers. We hypothesize that ε-PL destabilizes membranes in a carpet-like mechanism by interacting with negatively charged phospholipid head groups, which displace divalent cations and enforce a negative curvature folding on membranes that leads to formation of vesicles/micelles.

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