scholarly journals Increased 3′‐Phosphoadenosine‐5′‐phosphosulfate Levels in Engineered Escherichia coli Cell Lysate Facilitate the In Vitro Synthesis of Chondroitin Sulfate A

2019 ◽  
Vol 14 (9) ◽  
pp. 1800436 ◽  
Author(s):  
Abinaya Badri ◽  
Asher Williams ◽  
Ke Xia ◽  
Robert J. Linhardt ◽  
Mattheos A. G. Koffas
1978 ◽  
Vol 56 (6) ◽  
pp. 611-617 ◽  
Author(s):  
Joel H. Weiner ◽  
Elke Lohmeier ◽  
Anthony Schryvers

The two thousand Escherichia coli: Col E1 hybrid plasmid strains of the Clarke and Carbon colony bank (Clarke, L. &Carbon, J. (1976) Cell 9, 91–96) were screened by conjugation for those that correct the deficiency of a mutant unable to transport glycerol-3-phosphate. Six strains harbouring recombinant plasmids carrying the glpT region were identified and characterized with respect to plasmid size and transport properties. The initial rate of glycerol-3-phosphate transport in both whole cells and membrane vesicles prepared from such strains was elevated 3- to 10-fold over strains carrying random DNA inserts, whereas the Km of glycerol-3-phosphate transport was near 12 μM in both experimental and control strains. Four of the six glpT carrying plasmid strains demonstrated elevated levels of the anaerobic glycerol-3-phosphate dehydrogenase coded for by the neighbouring glpA gene.We have transferred the glpT hybrid plasmids into a minicell-producing strain of E. coli X1197 and have used the minicells for specific in vitro synthesis of plasmid-coded proteins. The glpT plasmids code for a 40 000 polypeptide which is localized in the periplasmic space. In addition, they code for a membrane-associated protein of 26 000 which may be the carrier polypeptide.


2019 ◽  
Vol 5 (2) ◽  
pp. 10
Author(s):  
Mohammad Kafaween ◽  
Abu Hilmi ◽  
Rao Khan ◽  
Mabrouka BOUACHA ◽  
Malik Amonov

1970 ◽  
Vol 48 (8) ◽  
pp. 893-907 ◽  
Author(s):  
W. Chefurka ◽  
A. Yapo ◽  
B. Nisman

The induction of β-galactosidase by a membranous fraction P1, prepared by digitonin lysis of spheroplasts of Escherichia coli, was studied in vitro. Electron micrographs of P1 show it to be a heterogeneous mixture of smooth vesicles, rough vesicles, rough vesicles attached to DNA, and ribosomes attached to DNA. P1 was subfractionated by differential centrifugation into an active heavy fraction, P4, and a relatively inactive light fraction, Pm. The P4 fraction consisted mainly of rough vesicles while the Pm fraction consisted mainly of smooth vesicles, but also of some rough vesicles. These vesicles of the Pm fraction were further separated by discontinuous sucrose gradient centrifugation.The induction of β-galactosidase by P1, P4, and Pm fractions was not related to mild contamination by unbroken viable spheroplasts. It was only partially sensitive to DNase and RNase. High concentrations of actinomycin D were required for complete inhibition of activity. This suggests that the transcription and translation components were shielded by the membranes. The synthetic activity of Pm was enhanced by fortification with DNA and/or S30. Only lac-containing DNA was active. The induction of β-galactosidase by this reconstituted system showed an absolute requirement for Pm membranes and for the inducer but only a partial requirement for nucleoside triphosphates. It was completely inhibited by puromycin and chloramphenicol.


2019 ◽  
Vol 20 (17) ◽  
pp. 4096 ◽  
Author(s):  
Ildikó Y. Tóth ◽  
Erzsébet Illés ◽  
Márta Szekeres ◽  
István Zupkó ◽  
Rodica Turcu ◽  
...  

Biopolymer coated magnetite nanoparticles (MNPs) are suitable to fabricate biocompatible magnetic fluid (MF). Their comprehensive characterization, however, is a necessary step to assess whether bioapplications are feasible before expensive in vitro and in vivo tests. The MNPs were prepared by co-precipitation, and after careful purification, they were coated by chondroitin-sulfate-A (CSA). CSA exhibits high affinity adsorption to MNPs (H-type isotherm). We could only make stable MF of CSA coated MNPs (CSA@MNPs) under accurate conditions. The CSA@MNP was characterized by TEM (size ~10 nm) and VSM (saturation magnetization ~57 emu/g). Inner-sphere metal–carboxylate complex formation between CSA and MNP was proved by FTIR-ATR and XPS. Electrophoresis and DLS measurements show that the CSA@MNPs at CSA-loading > 0.2 mmol/g were stable at pH > 4. The salt tolerance of the product improved up to ~0.5 M NaCl at pH~6.3. Under favorable redox conditions, no iron leaching from the magnetic core was detected by ICP measurements. Thus, the characterization predicts both chemical and colloidal stability of CSA@MNPs in biological milieu regarding its pH and salt concentration. MTT assays showed no significant impact of CSA@MNP on the proliferation of A431 cells. According to these facts, the CSA@MNPs have a great potential in biocompatible MF preparation for medical applications.


Sign in / Sign up

Export Citation Format

Share Document