scholarly journals Engineering yeast endosymbionts as a step toward the evolution of mitochondria

2018 ◽  
Vol 115 (46) ◽  
pp. 11796-11801 ◽  
Author(s):  
Angad P. Mehta ◽  
Lubica Supekova ◽  
Jian-Hua Chen ◽  
Kersi Pestonjamasp ◽  
Paul Webster ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Saccharomyces Cerevisiae ◽  
Intracellular Bacteria ◽  
Yeast Mutant ◽  
Lysosomal Degradation ◽  
Mitochondrial Evolution ◽  
X Ray ◽  
E Coli ◽  
Nonfermentable Carbon Source ◽  
Evolution Of Mitochondria

It has been hypothesized that mitochondria evolved from a bacterial ancestor that initially became established in an archaeal host cell as an endosymbiont. Here we model this first stage of mitochondrial evolution by engineering endosymbiosis betweenEscherichia coliandSaccharomyces cerevisiae. An ADP/ATP translocase-expressingE. coliprovided ATP to a respiration-deficientcox2yeast mutant and enabled growth of a yeast–E. colichimera on a nonfermentable carbon source. In a reciprocal fashion, yeast provided thiamin to an endosymbioticE. colithiamin auxotroph. Expression of several SNARE-like proteins inE. coliwas also required, likely to block lysosomal degradation of intracellular bacteria. This chimeric system was stable for more than 40 doublings, and GFP-expressingE. coliendosymbionts could be observed in the yeast by fluorescence microscopy and X-ray tomography. This readily manipulated system should allow experimental delineation of host–endosymbiont adaptations that occurred during evolution of the current, highly reduced mitochondrial genome.

scholarly journals Characterization of Escherichia coli DNA Lesions Generated within J774 Macrophages

2000 ◽  
Vol 182 (18) ◽  
pp. 5225-5230 ◽  
Author(s):  
Eliana Schlosser-Silverman ◽  
Maya Elgrably-Weiss ◽  
Ilan Rosenshine ◽  
Ron Kohen ◽  
Shoshy Altuvia
Keyword(s):  
Escherichia Coli ◽  
Dna Damage ◽  
Respiratory Burst ◽  
Defense Mechanism ◽  
Dna Lesions ◽  
Intracellular Bacteria ◽  
Bacterial Killing ◽  
Strand Breaks ◽  
E Coli ◽  
Dna Strand

ABSTRACT Macrophages are armed with multiple oxygen-dependent and -independent bactericidal properties. However, the respiratory burst, generating reactive oxygen species, is believed to be a major cause of bacterial killing. We exploited the susceptibility of Escherichia coli in macrophages to characterize the effects of the respiratory burst on intracellular bacteria. We show that E. coli strains recovered from J774 macrophages exhibit high rates of mutations. We report that the DNA damage generated inside macrophages includes DNA strand breaks and the modification 8-oxo-2′-deoxyguanosine, which are typical oxidative lesions. Interestingly, we found that under these conditions, early in the infection the majority of E. coli cells are viable but gene expression is inhibited. Our findings demonstrate that macrophages can cause severe DNA damage to intracellular bacteria. Our results also suggest that protection against the macrophage-induced DNA damage is an important component of the bacterial defense mechanism within macrophages.

scholarly journals Separation and Detection of Escherichia coli and Saccharomyces cerevisiae Using a Microfluidic Device Integrated with an Optical Fibre

Biosensors ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 40
Author(s):  
Mohd Kamuri ◽  
Zurina Zainal Abidin ◽  
Mohd Yaacob ◽  
Mohd Hamidon ◽  
Nurul Md Yunus ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Saccharomyces Cerevisiae ◽  
Optical Fibre ◽  
Flow Rate ◽  
Incident Light ◽  
Microfluidic Channel ◽  
Integrated System ◽  
Time Range ◽  
Constant Frequency ◽  
E Coli

This paper describes the development of an integrated system using a dry film resistant (DFR) microfluidic channel consisting of pulsed field dielectrophoretic field-flow-fractionation (DEP-FFF) separation and optical detection. The prototype chip employs the pulse DEP-FFF concept to separate the cells (Escherichia coli and Saccharomyces cerevisiae) from a continuous flow, and the rate of release of the cells was measured. The separation experiments were conducted by changing the pulsing time over a pulsing time range of 2–24 s and a flow rate range of 1.2–9.6 μ L min − 1 . The frequency and voltage were set to a constant value of 1 M Hz and 14 V pk-pk, respectively. After cell sorting, the particles pass the optical fibre, and the incident light is scattered (or absorbed), thus, reducing the intensity of the transmitted light. The change in light level is measured by a spectrophotometer and recorded as an absorbance spectrum. The results revealed that, generally, the flow rate and pulsing time influenced the separation of E. coli and S. cerevisiae. It was found that E. coli had the highest rate of release, followed by S. cerevisiae. In this investigation, the developed integrated chip-in-a lab has enabled two microorganisms of different cell dielectric properties and particle size to be separated and subsequently detected using unique optical properties. Optimum separation between these two microorganisms could be obtained using a longer pulsing time of 12 s and a faster flow rate of 9.6 μ L min − 1 at a constant frequency, voltage, and a low conductivity.

scholarly journals Elimination of Escherichia coli in Water Using Cobalt Ferrite Nanoparticles: Laboratory and Pilot Plant Experiments

Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2103
Author(s):  
Elmer Gastelo ◽  
Juan Montes de Oca ◽  
Edward Carpio ◽  
Juan Espinoza ◽  
Pilar García ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Pilot Plant ◽  
Cobalt Ferrite ◽  
Ferrite Nanoparticles ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
E Coli ◽  
Cobalt Ferrite Nanoparticles

This paper focuses on the synthesis of cobalt ferrite nanoparticles by the sol–gel method and their photocatalytic activity to eliminate bacteria in aqueous media at two different scales: in a laboratory reactor and a solar pilot plant. Cobalt ferrite nanoparticles were prepared using Co(II) and Fe(II) salts as precursors and cetyltrimethyl ammonium bromide as a surfactant. The obtained nanoparticles were characterized by X-ray diffraction, scanning and transmission electron microscopy. Escherichia coli (E. coli) strain ATCC 22922 was used as model bacteria for contact biocidal analysis carried out by disk diffusion method and photocatalysis under an ultraviolet A (UV-A) lamp for laboratory analysis and solar radiation (radiation below 350 W/m2 in a typical cloudy day) for the pilot plant analysis. The results showed that cobalt ferrite nanoparticles have an average diameter of (36 ± 20) nm and the X-ray diffraction pattern shows a cubic spinel structure. Using the disk diffusion technique, it was obtained inhibition zones of (17 ± 2) mm diameter. Results confirm the photocatalytic elimination of E. coli in water samples with remaining bacteria below 1% of the initial concentration during the experiment time (30 min for laboratory tests and 1.5 h for pilot plant tests).

scholarly journals RNA minihelices as model substrates for ATP/CTP:tRNA nucleotidyltransferase

1997 ◽  
Vol 327 (3) ◽  
pp. 847-851 ◽  
Author(s):  
Zengji LI ◽  
Yue SUN ◽  
L. David THURLOW
Keyword(s):  
Escherichia Coli ◽  
Saccharomyces Cerevisiae ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Single Base ◽  
Three Dimensional Structure ◽  
E Coli ◽  
Base Identity

Twenty-one RNA minihelices, resembling the coaxially stacked acceptor- /T-stems and T-loop found along the top of a tRNA's three-dimensional structure, were synthesized and used as substrates for ATP/CTP:tRNA nucleotidyltransferases from Escherichia coli and Saccharomyces cerevisiae. The sequence of nucleotides in the loop varied at positions corresponding to residues 56, 57 and 58 in the T-loop of a tRNA. All minihelices were substrates for both enzymes, and the identity of bases in the loop affected the interaction. In general, RNAs with purines in the loop were better substrates than those with pyrimidines, although no single base identity absolutely determined the effectiveness of the RNA as substrate. RNAs lacking bases near the 5ʹ-end were good substrates for the E. coli enzyme, but were poor substrates for that from yeast. The apparent Km values for selected minihelices were 2-3 times that for natural tRNA, and values for apparent Vmax were lowered 5-10-fold.

scholarly journals Microbial diversity beyond E. coli: new microbial worlds, new concepts in biology

2011 ◽  
Vol 32 (2) ◽  
pp. 73
Author(s):  
John A Fuerst
Keyword(s):  
Escherichia Coli ◽  
Saccharomyces Cerevisiae ◽  
Influenza Virus ◽  
Microbial Diversity ◽  
Microbial Evolution ◽  
E Coli ◽  
New Concepts ◽  
Wide Range ◽  
Classical Models ◽  
The Universe

Microbial diversity explores the universe of microorganisms beyond classical models such as Escherichia coli, influenza virus, or Saccharomyces cerevisiae. Exploring such new microbial worlds is essential for a microbiology which needs to learn about all the scientific and practical possibilities offered by billions of years of microbial evolution. Here we illustrate some examples of how studying a wide range of microbial diversity can assist microbiology as a fundamental and a practical science.

scholarly journals Effects of antibacterial compound of Saccharomyces cerevisiae from koumiss on immune function and caecal microflora of mice challenged with pathogenic Escherichia coli O8

2019 ◽  
Vol 88 (2) ◽  
pp. 233-241
Author(s):  
Yujie Chen ◽  
Chen Aorigele ◽  
Chunjie Wang ◽  
Wenqian Hou ◽  
Yunsheng Zheng ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Saccharomyces Cerevisiae ◽  
Immune Function ◽  
T Lymphocyte ◽  
Lymphocyte Subsets ◽  
Clinical Symptoms ◽  
Pathological Changes ◽  
T Lymphocyte Subsets ◽  
E Coli ◽  
Antibacterial Compound

The yeast Saccharomyces cerevisiae from koumiss has been shown to have antibacterial effects on Escherichia coli, possibly by producing antibacterial compound in metabolism; however, there is limited knowledge about its application in animal production. We therefore investigated the effects of an antibacterial compound of S. cerevisiae from koumiss on the immune function and caecal microflora of mice challenged with pathogenic Escherichia coli O8. Three groups were formed: negative control (NC), positive control (PC), and the antibacterial compound of S. cerevisiae at pH 2.0 (S2). Mice in the NC and PC groups were orally administered phosphate buffer solution (PBS) for 7 d. At 4 d, E. coli O8 was administered intraperitoneally in group PC. Mice in group S2 were first administered orally as mice in group NC, and subsequently intraperitoneally administered E. coli O8 as mice in group PC. Compared with the NC group, mice in the PC group displayed clinical symptoms and pathological changes in the small intestine. Small intestine villi in the S2 group also developed some histologically pathological changes but not as severe as in the PC group. Moreover, there was less mortality in the S2 group than in the PC group. In PC group, thymus indexes, immunoglobulin A (IgA) in serum and Bifidobacterium in caecum were decreased and E. coli in the caecum was increased. In the S2 group, CD8+ of T lymphocyte subsets in blood and Bifidobacterium in caecum were decreased, while spleen indexes, IgG, IgM in serum, and CD3+ of T lymphocyte subsets in blood were increased. This suggests that S2 can relieve clinical symptoms of mice challenged with pathogenic E. coli O8, enhance their immune function, and influence their caecal microflora. The study will provide a theoretical foundation for utilizing antibacterial compound of S. cerevisiae from koumiss for curative purposes.

scholarly journals Cloning of Phanerochaete chrysosporium leu2 by Complementation of Bacterial Auxotrophs and Transformation of Fungal Auxotrophs

1998 ◽  
Vol 64 (7) ◽  
pp. 2624-2629 ◽  
Author(s):  
Laura Schick Zapanta ◽  
Takefumi Hattori ◽  
Magarita Rzetskaya ◽  
Ming Tien
Keyword(s):  
Escherichia Coli ◽  
Saccharomyces Cerevisiae ◽  
Phanerochaete Chrysosporium ◽  
Expression Vector ◽  
Selectable Marker ◽  
Genomic Clone ◽  
Selectable Markers ◽  
E Coli ◽  
Number Of Genes ◽  
Isopropylmalate Dehydrogenase

ABSTRACT A Phanerochaete chrysosporium cDNA library was constructed in an expression vector that allows expression in bothEscherichia coli and Saccharomyces cerevisiae. This expression vector, λYES, contains the lacZ promoter for expression in E. coli and the GAL1 promoter for expression in yeast. A number of genes were cloned by complementation of bacterial amino acid auxotrophs. The cDNA encoding the β-isopropylmalate dehydrogenase from P. chrysosporiumwas characterized further. The genomic clone (gleu2) was subsequently isolated and was used successfully as a selectable marker to transform P. chrysosporium auxotrophs for LEU2. Protoplasts for transformation were prepared with readily obtained conidiospores rather than with basidiospores, which were used in previous P. chrysosporium transformation procedures. The method described here allows other genes to be isolated from P. chrysosporium for use as selectable markers.

scholarly journals Construction of Direct Z-Scheme Photocatalyst by Mg1.2Ti1.8O5 and g-C3N4 Nanosheets toward Photocatalytic H2 Production and Disinfection

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Sijia Gu ◽  
Dan Zhang ◽  
Shirong Luo ◽  
Heng Yang
Keyword(s):  
Escherichia Coli ◽  
Photocatalytic Performance ◽  
Diffuse Reflectance Spectroscopy ◽  
Sol Gel ◽  
H2 Production ◽  
X Ray ◽  
E Coli ◽  
Carrier Separation ◽  
Positive Valence ◽  
Calcination Method

Exploring a novel and efficient photocatalyst is the key research goal to relieve energy and environmental issues. Herein, Z-scheme heterojunction composites were successfully fabricated by loading g-C3N4 nanosheets (CN) on the surface of Mg1.2Ti1.8O5 nanoflakes (MT) through a simple sol-gel method followed by the calcination method. The crystalline phase, morphologies, specific surface area, and optical and electrochemical performance of the samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy-disperse X-ray spectroscopy (EDS), Brunauer-Emmett-Teller (BET), diffuse reflectance spectroscopy (DRS), and electrochemical measurements. Considering the suitable band structures of the components, the photocatalytic performance was evaluated by photocatalytic H2O splitting and photocatalytic inactivation of Escherichia coli (E. coli). Among the samples, MT/CN-10 (the molar percentage of melamine to as-obtained Mg-Ti gel was 10%) shows superior photocatalytic performance, which the average H2 production rate was 3.57 and 7.24 times higher than those of MT and CN alone. Additionally, the efficiency of inactivating Escherichia coli (E. coli) over MT/CN-10 was 1.95 and 2.06 times higher as compared to pure MT and CN, respectively. The enhancement of the photocatalytic performance was attributed to the advantages of the extremely negative conduction band (CB) of CN and the extremely positive valence band (VB) of MT, the enhanced light absorption, and more efficient photogenerated charge carrier separation.

scholarly journals Cloning of Thalassiosira pseudonana’s Mitochondrial Genome in Saccharomyces cerevisiae and Escherichia coli

Biology ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 358
Author(s):  
Ryan R. Cochrane ◽  
Stephanie L. Brumwell ◽  
Arina Shrestha ◽  
Daniel J. Giguere ◽  
Samir Hamadache ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Saccharomyces Cerevisiae ◽  
Mitochondrial Genome ◽  
Phaeodactylum Tricornutum ◽  
Genome Engineering ◽  
Genome Instability ◽  
Thalassiosira Pseudonana ◽  
Genome Integrity ◽  
Mitochondrial Genomes ◽  
E Coli

Algae are attractive organisms for biotechnology applications such as the production of biofuels, medicines, and other high-value compounds due to their genetic diversity, varied physical characteristics, and metabolic processes. As new species are being domesticated, rapid nuclear and organelle genome engineering methods need to be developed or optimized. To that end, we have previously demonstrated that the mitochondrial genome of microalgae Phaeodactylum tricornutum can be cloned and engineered in Saccharomyces cerevisiae and Escherichia coli. Here, we show that the same approach can be used to clone mitochondrial genomes of another microalga, Thalassiosira pseudonana. We have demonstrated that these genomes can be cloned in S. cerevisiae as easily as those of P. tricornutum, but they are less stable when propagated in E. coli. Specifically, after approximately 60 generations of propagation in E. coli, 17% of cloned T. pseudonana mitochondrial genomes contained deletions compared to 0% of previously cloned P. tricornutum mitochondrial genomes. This genome instability is potentially due to the lower G+C DNA content of T. pseudonana (30%) compared to P. tricornutum (35%). Consequently, the previously established method can be applied to clone T. pseudonana’s mitochondrial genome, however, more frequent analyses of genome integrity will be required following propagation in E. coli prior to use in downstream applications.

scholarly journals Excision repair functions in Saccharomyces cerevisiae recognize and repair methylation of adenine by the Escherichia coli dam gene.

1986 ◽  
Vol 6 (10) ◽  
pp. 3555-3558 ◽  
Author(s):  
M F Hoekstra ◽  
R E Malone
Keyword(s):  
Escherichia Coli ◽  
Saccharomyces Cerevisiae ◽  
Excision Repair ◽  
Yeast Cells ◽  
Pyrimidine Dimer ◽  
Repair System ◽  
E Coli

Unlike the DNA of higher eucaryotes, the DNA of Saccharomyces cerevisiae (bakers' yeast) is not methylated. Introduction of the Escherichia coli dam gene into yeast cells results in methylation of the N-6 position of adenine. The UV excision repair system of yeast cells specifically responds to the methylation, suggesting that it is capable of recognizing modifications which do not lead to major helix distortion. The UV repair functions examined in this report are involved in the incision step of pyrimidine dimer repair. These observations may have relevance to the rearrangements and recombination events observed when yeast or higher eucaryotic cells are transformed or transfected with DNA grown in E. coli.

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