Bioproduction of Eriodictyol By Escherichia Coli Engineered Co-Culture

Abstract Eriodictyol is a flavonoid in the flavanones subclass. It is abundantly present in a wide range of medicinal plants, citrus fruits, and vegetables. In addition, eriodictyol owns numerous importantly medicinal bioactivities such as inhibition of proliferation, metastasis and induction of apoptosis in glioma cells or inhibition of glioblastoma migration, and invasion. This study described the heterologous production of eriodictyol by E. coli based co-culture engineering system from the initial substrate as D-glucose. Notably, the upstream module was composed of genes for synthesis of p-coumaric acid (pCA) from D-glucose. The downstream module consisted of genes for the synthesis of eriodictyol from p-coumaric acid. The maximal result of eryodictyol was achieved 51.5 mg/L using optimal culture conditions, while mono-culture was only achieved 21.3 mg/L. In conclusion, co-culture was the efficiently alternative approach for the synthesis of eriodictyol and other natural products.

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Evaluation of bacterial proliferation with a microfluidic-based device: Antibiochip

10.1101/792358 ◽

2019 ◽

Author(s):

Valentina Gallo ◽

Alessia Ruiba ◽

Massimo Zanin ◽

Paolo Begnamino ◽

Sabina Ledda ◽

...

Keyword(s):

Laboratory Medicine ◽

Culture Conditions ◽

Inhibition Of Proliferation ◽

Standard Methods ◽

E Coli ◽

Bacterial Proliferation ◽

Microbial Cultures ◽

Novel Approach ◽

Microbial Strains ◽

The Relationship

AbstractThe measurement of the proliferation (and the relevant inhibition of proliferation) of microbes is used in different settings, from industry to laboratory medicine. Thus, in this study, the capacity of the Antibiochip (ELTEK spa), a microfluidic-based device, to measure the amount of E. coli in certain culture conditions, was evaluated. An Antibiochip is composed of V-shaped microchannels, and the amount of microparticles (such as microbes) is measured by the surface of the pellet after centrifugation. In the present study, different geometries, volumes and times were analyzed. When the best conditions were identified, serial dilutions of microbial cultures were tested to validate the linearity of the results. Then, with the use of wild E. coli strains isolated from medical samples, the relationship between bacterial susceptibility to antibiotics (gentamicin, amikacin and ceftriaxone) measured by standard methods and that measured by the Antibiochip was evaluated. In this report, the good quality performances of the methods, their linearity and the capacity to identify susceptible microbial strains after 60 minutes of incubation are shown. These results represent a novel approach for ultrarapid antibiograms in clinics.

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Small Molecule Permeation Across Membrane Channels: Chemical Modification to Quantify Transport Across OmpF

10.26434/chemrxiv.7040354.v1 ◽

2018 ◽

Author(s):

Jiajun Wang ◽

Jayesh Arun Bafna ◽

Satya Prathyusha Bhamidimarri ◽

Mathias Winterhalter

Keyword(s):

Dwell Time ◽

Covalent Binding ◽

Channel Structure ◽

Ion Current ◽

E Coli ◽

Current Fluctuation ◽

Wide Range ◽

Outer Membrane Channel ◽

Biological Channels ◽

Constriction Region

Biological channels facilitate the exchange of small molecules across membranes, but surprisingly there is a lack of general tools for the identification and quantification of transport (i.e., translocation and binding). Analyzing the ion current fluctuation of a typical channel with its constriction region in the middle does not allow a direct conclusion on successful transport. For this, we created an additional barrier acting as a molecular counter at the exit of the channel. To identify permeation, we mainly read the molecule residence time in the channel lumen as the indicator whether the molecule reached the exit of the channel. As an example, here we use the well-studied porin, OmpF, an outer membrane channel from E. coli. Inspection of the channel structure suggests that aspartic acid at position 181 is located below the constriction region (CR) and we subsequently mutated this residue to cysteine, where else cysteine free and functionalized it by covalent binding with 2-sulfonatoethyl methanethiosulfonate (MTSES) or the larger glutathione (GLT) blockers. Using the dwell time as the signal for transport, we found that both mono-arginine and tri-arginine permeation process is prolonged by 20% and 50% respectively through OmpFE181CMTSES, while the larger sized blocker modification OmpFE181CGLT drastically decreased the permeation of mono-arginine by 9-fold and even blocked the pathway of the tri-arginine. In case of the hepta-arginine as substrate, both chemical modifications led to an identical ‘blocked’ pattern observed by the dwell time of ion current fluctuation of the OmpFwt. As an instance for antibiotic permeation, we analyzed norfloxacin, a fluoroquinolone antimicrobial agent. The modulation of the interaction dwell time suggests possible successful permeation of norfloxacin across OmpFwt. This approach may discriminate blockages from translocation events for a wide range of substrates. A potential application could be screening for scaffolds to improve the permeability of antibiotics.

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An Improved Membrane Filtration Method for Enumeration of Faecal Coliforms and E. Coli by a Fluorogenic β-Glucuronidase Assay

Water Science & Technology ◽

10.2166/wst.1993.0357 ◽

1993 ◽

Vol 27 (3-4) ◽

pp. 267-270 ◽

Cited By ~ 4

Author(s):

M. T. Augoustinos ◽

N. A. Grabow ◽

B. Genthe ◽

R. Kfir

Keyword(s):

Escherichia Coli ◽

Water Samples ◽

Membrane Filtration ◽

Faecal Coliforms ◽

Environmental Waters ◽

Filtration Method ◽

E Coli ◽

Wide Range ◽

Pure Cultures ◽

Glucuronidase Assay

A fluorogenic β-glucuronidase assay comprising membrane filtration followed by selective enumeration on m-FC agar at 44.5°C and further confirmation using tlie 4-metliylumbelliferyl-β-D-glucuronide (MUG) containing medium was evaluated for the detection of Escherichia coli in water. A total of 200 typical blue and non-typical blue colonies were isolated from sea and fresh water samples using initial selective enumeration on m-FC agar. Pure cultures of the selected colonies were further tested using the MUG assay and identified using the API 20E method. Of the colonies tested which were shown to be positive using the MUG assay 99.4% were Escherichia coli. The results of this study indicate the combination of the m-FC method followed by the MUG assay to be highly efficient for the selection and confirmation of E. coli from a wide range of environmental waters.

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Dehydroandrographolide Inhibits Osteosarcoma Cell Growth and Metastasis by Targeting SATB2-mediated EMT

Anti-Cancer Agents in Medicinal Chemistry ◽

10.2174/1871520619666190705121614 ◽

2019 ◽

Vol 19 (14) ◽

pp. 1728-1736

Author(s):

Xuefeng Liu ◽

Yonggang Fan ◽

Jing Xie ◽

Li Zhang ◽

Lihua Li ◽

...

Keyword(s):

Cell Cycle ◽

Wound Healing ◽

Cell Growth ◽

Brdu Incorporation ◽

Migration And Invasion ◽

Therapeutic Drug ◽

Osteosarcoma Cell ◽

Dependent Manner ◽

Inhibition Of Proliferation ◽

Predominant Component

Background:The 12-hydroxy-14-dehydroandrographolide (DP) is a predominant component of the traditional herbal medicine Andrographis paniculata (Burm. f.) Nees (Acanthaceae). Recent studies have shown that DP exhibits potent anti-cancer effects against oral and colon cancer cells.Objective:This investigation examined the potential effects of DP against osteosarcoma cell.Methods:A cell analyzer was used to measure cell viability. The cell growth and proliferation were performed by Flow cytometry and BrdU incorporation assay. The cell migration and invasion were determined by wound healing and transwell assay. The expression of EMT related proteins was examined by Western blot analysis.Results:In this study, we found that DP treatment repressed osteosarcoma (OS) cell growth in a dose-dependent manner. DP treatment significantly inhibited OS cell proliferation by arresting the cell cycle at G2/M phase. In addition, DP treatment effectively inhibited the migration and invasion abilities of OS cells through wound healing and Transwell tests. Mechanistic studies revealed that DP treatment effectively rescued the epithelialmesenchymal transition (EMT), while forced expression of SATB2 in OS cells markedly reversed the pharmacological effect of DP on EMT.Conclusion:Our data demonstrated that DP repressed OS cell growth through inhibition of proliferation and cell cycle arrest; DP also inhibited metastatic capability of OS cells through a reversal of EMT by targeting SATB2. These findings demonstrate DP’s potential as a therapeutic drug for OS treatment.

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3D-Printed Nanocellulose-Based Cushioning–Antibacterial Dual-Function Food Packaging Aerogel

Molecules ◽

10.3390/molecules26123543 ◽

2021 ◽

Vol 26 (12) ◽

pp. 3543

Author(s):

Wei Zhou ◽

Jiawei Fang ◽

Shuwei Tang ◽

Zhengguo Wu ◽

Xiaoying Wang

Keyword(s):

3D Printing ◽

Food Packaging ◽

Fruits And Vegetables ◽

Antibacterial Effect ◽

Dual Function ◽

Printing Technology ◽

E Coli ◽

3D Printing Technology ◽

The Core ◽

3D Printed

Cushioning and antibacterial packaging are the requirements of the storage and transportation of fruits and vegetables, which are essential for reducing the irreversible quality loss during the process. Herein, the composite of carboxymethyl nanocellulose, glycerin, and acrylamide derivatives acted as the shell and chitosan/AgNPs were immobilized in the core by using coaxial 3D-printing technology. Thus, the 3D-printed cushioning–antibacterial dual-function packaging aerogel with a shell–core structure (CNGA/C–AgNPs) was obtained. The CNGA/C–AgNPs packaging aerogel had good cushioning and resilience performance, and the average compression resilience rate was more than 90%. Although AgNPs was slowly released, CNGA/C–AgNPs packaging aerogel had an obvious antibacterial effect on E. coli and S. aureus. Moreover, the CNGA/C–AgNPs packaging aerogel was biodegradable. Due to the customization capabilities of 3D-printing technology, the prepared packaging aerogel can be adapted to more application scenarios by accurately designing and regulating the microstructure of aerogels, which provides a new idea for the development of food intelligent packaging.

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Machine learning for multi-dimensional optimisation and predictive visualisation of laser machining

Journal of Intelligent Manufacturing ◽

10.1007/s10845-020-01717-4 ◽

2021 ◽

Author(s):

Michael D. T. McDonnell ◽

Daniel Arnaldo ◽

Etienne Pelletier ◽

James A. Grant-Jacob ◽

Matthew Praeger ◽

...

Keyword(s):

Short Pulse ◽

Surface Texturing ◽

Laser Surface Texturing ◽

Laser Machining ◽

Laser Materials ◽

Parameter Optimisation ◽

Short Pulse Laser ◽

Alternative Approach ◽

Highly Nonlinear ◽

Wide Range

AbstractInteractions between light and matter during short-pulse laser materials processing are highly nonlinear, and hence acutely sensitive to laser parameters such as the pulse energy, repetition rate, and number of pulses used. Due to this complexity, simulation approaches based on calculation of the underlying physical principles can often only provide a qualitative understanding of the inter-relationships between these parameters. An alternative approach such as parameter optimisation, often requires a systematic and hence time-consuming experimental exploration over the available parameter space. Here, we apply neural networks for parameter optimisation and for predictive visualisation of expected outcomes in laser surface texturing with blind vias for tribology control applications. Critically, this method greatly reduces the amount of experimental laser machining data that is needed and associated development time, without negatively impacting accuracy or performance. The techniques presented here could be applied in a wide range of fields and have the potential to significantly reduce the time, and the costs associated with laser process optimisation.

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Urinary Excretion and Bactericidal Activities of a Single Oral Dose of 400 Milligrams of Fleroxacin versus a Single Oral Dose of 800 Milligrams of Pefloxacin in Healthy Volunteers

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.42.7.1659 ◽

1998 ◽

Vol 42 (7) ◽

pp. 1659-1665 ◽

Cited By ~ 15

Author(s):

Kurt G. Naber ◽

Ursula Theuretzbacher ◽

Martina Kinzig ◽

Orlin Savov ◽

Fritz Sörgel

Keyword(s):

Oral Dose ◽

Healthy Volunteers ◽

Single Oral Dose ◽

E Coli ◽

Wide Range ◽

The Mean ◽

Bactericidal Activities ◽

Tract Infections ◽

Time Kill ◽

Randomized Crossover Study

ABSTRACT Twelve healthy volunteers participated in this randomized crossover study to compare the concentrations and recovery levels of fleroxacin and pefloxacin in urine and to assess their bactericidal activities against 12 strains of urinary pathogens with different susceptibilities over a wide range of MICs. The volunteers received a single oral dose of 400 mg of fleroxacin or 800 mg of pefloxacin. The mean cumulative renal excretion of unchanged fleroxacin,N-demethyl-fleroxacin, and N-oxide-fleroxacin accounted for 67, 7, and 6% of the total dose, respectively. The total urinary recovery of pefloxacin and the active metabolite norfloxacin was 34%. In the time-kill and the urinary bactericidal titer (UBT) studies, only the subjects’ urine not supplemented with broth was used. With most tested organisms and both quinolones it took more than 8 h to achieve a reduction in CFU of 99.9% (3 log units). Overall, there was a good correlation between UBTs and MICs for the strains. Against Escherichia coli ATCC 25922 the median UBTs were similar for both antibiotics and at least 1:8 for 96 h; against the E. coli strain for which the MIC was 0.5 μg/ml the UBT was at least 1:4 for 48 h. The UBTs of both drugs against Klebsiella pneumoniae were at least 1:16 for 72 h. The UBTs for Staphylococcus aureus (the MIC for which was 16 μg/ml) of both antibiotics were low, and in some of the samples, no bactericidal titers were observed. UBTs for Proteus mirabilis of pefloxacin are significantly higher than those of fleroxacin. For Pseudomonas aeruginosa the median UBTs were present for the 24-to-48-h interval. The same is true forEnterococcus faecalis. Against Staphylococcus saprophyticus, UBTs were present for at least 48 h with both quinolones. Overall, a single oral dose of 400 mg of fleroxacin exhibits UBTs comparable to those of 800 mg of pefloxacin. Therefore, it may be expected that half of the dose of fleroxacin gives comparable results in the treatment of urinary tract infections; this should be substantiated in comparative clinical trials.

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Activation of the receptor tyrosine kinase RET improves long-term hematopoietic stem cell outgrowth and potency

Blood ◽

10.1182/blood.2020006302 ◽

2020 ◽

Vol 136 (22) ◽

pp. 2535-2547 ◽

Cited By ~ 5

Author(s):

W. Grey ◽

R. Chauhan ◽

M. Piganeau ◽

H. Huerga Encabo ◽

M. Garcia-Albornoz ◽

...

Keyword(s):

Intracellular Signaling ◽

Culture Conditions ◽

Cellular Growth ◽

Great Promise ◽

Bone Marrow Niche ◽

Hematopoietic Stem ◽

Intracellular Signaling Pathway ◽

Wide Range

Abstract Expansion of human hematopoietic stem cells (HSCs) is a rapidly advancing field showing great promise for clinical applications. Recent evidence has implicated the nervous system and glial family ligands (GFLs) as potential drivers of hematopoietic survival and self-renewal in the bone marrow niche; how to apply this process to HSC maintenance and expansion has yet to be explored. We show a role for the GFL receptor, RET, at the cell surface of HSCs in mediating sustained cellular growth, resistance to stress, and improved cell survival throughout in vitro expansion. HSCs treated with the key RET ligand/coreceptor complex, glial-derived neurotrophic factor and its coreceptor, exhibit improved progenitor function at primary transplantation and improved long-term HSC function at secondary transplantation. Finally, we show that RET drives a multifaceted intracellular signaling pathway, including key signaling intermediates protein kinase B, extracellular signal-regulated kinase 1/2, NF-κB, and p53, responsible for a wide range of cellular and genetic responses that improve cell growth and survival under culture conditions.

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Vibrio cholerae Triggers SOS and Mutagenesis in Response to a Wide Range of Antibiotics: a Route towards Multiresistance

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01549-10 ◽

2011 ◽

Vol 55 (5) ◽

pp. 2438-2441 ◽

Cited By ~ 107

Author(s):

Zeynep Baharoglu ◽

Didier Mazel

Keyword(s):

Escherichia Coli ◽

Antibiotic Resistance ◽

Vibrio Cholerae ◽

Fluorescent Protein ◽

Resistance Development ◽

Content Type ◽

E Coli ◽

Wide Range ◽

Green Fluorescent ◽

Regulated Promoters

ABSTRACTAntibiotic resistance development has been linked to the bacterial SOS stress response. InEscherichia coli, fluoroquinolones are known to induce SOS, whereas other antibiotics, such as aminoglycosides, tetracycline, and chloramphenicol, do not. Here we address whether various antibiotics induce SOS inVibrio cholerae. Reporter green fluorescent protein (GFP) fusions were used to measure the response of SOS-regulated promoters to subinhibitory concentrations of antibiotics. We show that unlike the situation withE. coli, all these antibiotics induce SOS inV. cholerae.

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4-Aminobutyrate (GABA) transporters from the amine-polyamine-choline superfamily: substrate specificity and ligand recognition profile of the 4-aminobutyrate permease from Bacillus subtilis

Biochemical Journal ◽

10.1042/bj3330565 ◽

1998 ◽

Vol 333 (3) ◽

pp. 565-571 ◽

Cited By ~ 18

Author(s):

Casey E. BRECHTEL ◽

Steven C. KING

Keyword(s):

Bacillus Subtilis ◽

Culture Conditions ◽

Ligand Recognition ◽

Open Chain ◽

Conformationally Constrained ◽

E Coli ◽

Gaba Transporters ◽

Transport Defect ◽

Gaba Analogues ◽

Limited Culture

A previous study [Ferson, Wray and Fisher (1996) Mol. Microbiol. 22, 693–701] has shown that transposon-mediated disruption of a protein 47% identical to the Escherichia coli GABA (4-aminobutyrate) transporter abolishes the ability of nitrogen-limited culture conditions to induce expression of a GABA transport activity in Bacillus subtilis. Here it is demonstrated directly that the B. subtilis GABA permease (gabP) gene can complement the transport defect in the gabP-negative E. colistrain. Unexpectedly, the ligand-recognition profile of the B. subtilis GabP was found to differ substantially from that of the highly homologous E. coli GabP. Unlike the E. coli GabP, the B. subtilis GabP: (i) exhibits approx. equal preference for the 3-carbon (β-alanine, Km = 9.6 µM) and the 4-carbon (GABA, Km = 37 µM) amino acids, and (ii) resists inhibition by bulky, conformationally constrained compounds (e.g. nipecotic acid, guvacine), which are active against GABA transporters from brain. The present study shows additionally that the B. subtilis GabP can translocate several open-chain GABA analogues (3-aminobutyrate, 3-aminopropanoate, cis-4-aminobutenoate) across the membrane via counterflow against [3H]GABA. Thus, consistent with the idea that the ligand-recognition domain of the B. subtilis GabP is less spacious than that of the close homologue from E. coli, the former exhibits more stringent requirements than the latter for substrate recognition and translocation. These distinct functional characteristics of the E. coli and B. subtilis GABA transporters provide a basis by which to identify ligand-recognition domains within the amine-polyamine-choline transporter superfamily.

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