Buoyant density of Escherichia coli is determined solely by the osmolarity of the culture medium

1995 ◽  
Vol 164 (2) ◽  
pp. 155-157 ◽  
Author(s):  
W. W. Baldwin ◽  
Richard Myer ◽  
Erika Anderson ◽  
Arthur L. Koch
Keyword(s):  
Escherichia Coli ◽  
Culture Medium ◽  
Buoyant Density

scholarly journals The Isolation and Oharacterization of An Rna Bacteriophage

1964 ◽  
Vol 17 (3) ◽  
pp. 719 ◽  
Author(s):  
CI Davern
Keyword(s):  
Escherichia Coli ◽  
Dna Synthesis ◽  
Culture Medium ◽  
Buoyant Density ◽  
Sedimentation Coefficient ◽  
Caesium Chloride ◽  
Specific Phage ◽  
K 12 ◽  
Male Specific ◽  
Rna Phage

An enrichment procedure for the isolation of RNA bacteriophage is described. The method involves the inoculation of sewage samples into cultures of Escherichia coli K-12 Hfr under conditions where DNA synthesis is restricted by the addition of 5-fiuorodeoxyuridine to the culture medium. Six phage isolates were made and all of them were shown to be male-specific. One of the male-specific phage was further characterized as an RNA phage, having very similar properties to RNA phage already isolated in other parts oftha world. This RNA phage has a buoyant density of 1�42 g/cm3 in caesium chloride. and has a sedimentation coefficient of 79'5 Sin O'Ol:M Tria-HOI buffer, pH 7� 4, at 20�0.

Study on Optimization of Fermentation Condition for Nitrilase-Producer Escherichia Coli BL21 (DE3)/pET-Nit

2011 ◽  
Vol 175-176 ◽  
pp. 192-196 ◽  
Author(s):  
Li Li Feng ◽  
Jian Fei Zhang ◽  
Hui Luo ◽  
Zheng Li ◽  
Hong Jie Zhang
Keyword(s):  
Escherichia Coli ◽  
Recombinant Strain ◽  
Culture Medium ◽  
Culture Conditions ◽  
Fermentation Condition ◽  
Hydrogen Phosphate ◽  
Strain Bl21 ◽  
Initial Ph ◽  
Potassium Hydrogen ◽  
Optimization Of Fermentation

The paper concentrated on the optimization of the recombinant strain BL21 (DE3)-PE7-Nit. The component of culture medium and the culture conditions were optimized. The optimized medium was: yeast extract 10 g/l, L-glutamate sodium 8 g/l, MgSO4.7H2O 0.7 g/l, Isopropyl-β-D-thiogalactopyranoside 0.3 mmol/L, potassium hydrogen phosphate 0.5 g / L, phosphate Potassium 0.5 g / L and the culture condition was: initial pH 7.0, inoculum 2%. The result showed that the activity of nitrilase prepared with these conditions increased by 130.37 % through optimization.

P–218 Analysis of the occurrence of microbial contamination in IVF culture system and the effect of microorganisms on embryo development and clinical outcomes

2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
F Du ◽  
R Li ◽  
Q Zhang ◽  
W Wang
Keyword(s):  
Escherichia Coli ◽  
In Vitro Culture ◽  
Clinical Outcomes ◽  
Embryo Transfer ◽  
Follicular Fluid ◽  
Culture System ◽  
Microbial Contamination ◽  
Culture Medium ◽  
Ivf Et

Abstract Study question what is the source, prevalence, and influence of microbial contamination on in vitro fertilization (IVF) and embryo transfer (ET) cycles? Summary answer Microbial contamination mainly occurs on Day 2, most caused by Escherichia coli carried with semen. ICSI could prevent contamination effectively and get good clinical outcomes. What is known already Microbial contamination occurs in IVF-ET system occasionally, which is hard to stop happening. The IVF culture system and laboratory environment, the patients’ follicular fluid and semen are not absolutely sterile, while the antibiotics in culture medium isn’t effective for all microbe types, and the artificial operations may bring in microbes. Generally, microbial contamination leads to degradation of embryos, reduction the number of embryos available, and infection of female reproductive tract, which would increase the cost of patients’ time, money, and bring psychological damages. A better understanding of embryo contamination in IVF culture system is of added value. Study design, size, duration A total of 29583 IVF-ET cycles were enrolled in this prospective observational study, from January 2010 to December 2020, included 70 microbial contamination cycles discovered in Day1-Day3 (D1-D3) of in vitro culture. Follicular fluid and semen saved on oocyte retrieval day, and culture medium contaminated were examined and identified for microorganisms at each contamination cycle. Participants/materials, setting, methods Compared the contamination rate of different insemination methods (IVF/ICSI/IVF+ICSI), different in vitro culture days (D1-D3), and different samples examination (follicular fluid, semen, culture medium) respectively, identified the source of microorganism types, compared the IVF culture outcomes and clinical outcomes between total contamination group (TC group, 42 cases) and partial contamination group (PC group, 28 cases). Main results and the role of chance A total of 70 microbial contamination cases occurred in 29583 oocyte retrieving cycles (0.24%), and it was observed only in IVF embryos but never in ICSI (Intracytoplasmic sperm injection) embryos. 38 contamination cases occurred on D2 with a highest ratio (54.3%) compared to D1 (32.9%) and D3(12.9%); Compared with follicular fluid, semen was the main cause inducing contamination from D1 to D3, and Escherichia coli in semen and culture medium, Enterococcus faecalis in follicular fluid proved to be the most common sources. Compared with TC group, the PC group showed a lower rate of No-available embryos (21.4% vs 81.0%) and a higher rate of blastocyst formation (41.2% vs 28.6%), In addition, the clinical pregnancy rate of PC group was higher than that of TC group in both fresh and frozen-thawed embryo transfer cycles (31.3% vs 16.7%, 38.5% vs 0.0%). Limitations, reasons for caution Further study is still necessary to better understand the sources that induce microbial contamination embryos, and more efficient methods are required to remove the microbes on these contaminated embryos so as better develop and manage a sterile micro-environment for successful embryo growth. Wider implications of the findings: The differential embryonic microbe types associated to different IVF culture and clinical outcomes in patients undergoing IVF-ET might have profound implications for understanding the microbial sources and making a better management of IVF culture system. Trial registration number Not applicable

Reduction of Selenite and Detoxification of Elemental Selenium by the Phototrophic BacteriumRhodospirillum rubrum

1999 ◽  
Vol 65 (11) ◽  
pp. 4734-4740 ◽  
Author(s):  
J. Kessi ◽  
M. Ramuz ◽  
E. Wehrli ◽  
M. Spycher ◽  
R. Bachofen
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Cell Density ◽  
Culture Medium ◽  
Rhodospirillum Rubrum ◽  
Buoyant Density ◽  
Elemental Selenium ◽  
Selenite Reduction ◽  
Final Cell Density ◽  
Cell Densities

ABSTRACT The effect of selenite on growth kinetics, the ability of cultures to reduce selenite, and the mechanism of detoxification of selenium were investigated by using Rhodospirillum rubrum. Anoxic photosynthetic cultures were able to completely reduce as much as 1.5 mM selenite, whereas in aerobic cultures a 0.5 mM selenite concentration was only reduced to about 0.375 mM. The presence of selenite in the culture medium strongly affected cell division. In the presence of a selenite concentration of 1.5 mM cultures reached final cell densities that were only about 15% of the control final cell density. The cell density remained nearly constant during the stationary phase for all of the selenite concentrations tested, showing that the cells were not severely damaged by the presence of selenite or elemental selenium. Particles containing elemental selenium were observed in the cytoplasm, which led to an increase in the buoyant density of the cells. Interestingly, the change in the buoyant density was reversed after selenite reduction was complete; the buoyant density of the cells returned to the buoyant density of the control cells. This demonstrated that R. rubrum expels elemental selenium across the plasma membrane and the cell wall. Accordingly, electron-dense particles were more numerous in the cells during the reduction phase than after the reduction phase.

scholarly journals Membrane Association of the Escherichia coli Enterobactin Synthase Proteins EntB/G, EntE, and EntF

2000 ◽  
Vol 182 (6) ◽  
pp. 1768-1773 ◽  
Author(s):  
Feras M. Hantash ◽  
Charles F. Earhart
Keyword(s):  
Escherichia Coli ◽  
Final Stage ◽  
Membrane Fraction ◽  
Osmotic Shock ◽  
Buoyant Density ◽  
Membrane Association ◽  
Cytosolic Proteins ◽  
Outer Membranes ◽  
Cytoplasmic Proteins ◽  
A Minor

ABSTRACT The cytosolic proteins EntE, EntF, and EntB/G, which areEscherichia coli enzymes necessary for the final stage of enterobactin synthesis, are released by osmotic shock. Here, consistent with the idea that cytoplasmic proteins found in shockates have an affinity for membranes, a small fraction of each was found in membrane preparations. Two procedures demonstrated that the enzymes were enriched in a minor membrane fraction of buoyant density intermediate between that of cytoplasmic and outer membranes, providing indirect support for the notion that these proteins have a role in enterobactin excretion as well as synthesis.

Attachment of enterohemorrhagic Escherichia coli to the surface of beef and a culture medium

LWT ◽  
2007 ◽  
Vol 40 (2) ◽  
pp. 249-254 ◽  
Author(s):  
Jinru Chen ◽  
Michelle L. Rossman ◽  
Dharmendrasingh M. Pawar
Keyword(s):  
Escherichia Coli ◽  
Culture Medium ◽  
Enterohemorrhagic Escherichia Coli

scholarly journals Uropathogenic Escherichia coli Biofilm-Forming Capabilities are not Predictable from Clinical Details or from Colonial Morphology

Diseases ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 11 ◽  
Author(s):  
Shane Whelan ◽  
Mary Claire O’Grady ◽  
Dan Corcoran ◽  
Karen Finn ◽  
Brigid Lucey
Keyword(s):  
Escherichia Coli ◽  
Biofilm Formation ◽  
Culture Medium ◽  
Recurrent Infection ◽  
Positive Control ◽  
Uropathogenic Escherichia Coli ◽  
E Coli ◽  
Recurrent Uti ◽  
Colonial Morphology ◽  
The Difference

Antibiotic resistance is increasing to an extent where efficacy is not guaranteed when treating infection. Biofilm formation has been shown to complicate treatment, whereby the formation of biofilm is associated with higher minimum inhibitory concentration values of antibiotic. The objective of the current paper was to determine whether biofilm formation is variable among uropathogenic Escherichia coli isolates and whether formation is associated with recurrent urinary tract infection (UTI), and whether it can be predicted by phenotypic appearance on culture medium A total of 62 E. coli isolates that were reported as the causative agent of UTI were studied (33 from patients denoted as having recurrent UTI and 29 from patients not specified as having recurrent UTI). The biofilm forming capability was determined using a standard microtitre plate method, using E. coli ATCC 25922 as the positive control. The majority of isolates (93.6%) were found to be biofilm formers, whereby 81% were denoted as strong or very strong producers of biofilm when compared to the positive control. Through the use of a Wilcox test, the difference in biofilm forming propensity between the two patient populations was found to not be statistically significant (p = 0.5). Furthermore, it was noted that colony morphology was not a reliable predictor of biofilm-forming propensity. The findings of this study indicate that biofilm formation is very common among uropathogens, and they suggest that the biofilm-forming capability might be considered when treating UTI. Clinical details indicating a recurrent infection were not predictors of biofilm formation.

scholarly journals Influence of culture medium on the production of eif antigen from Leishmania chagasi in recombinant Escherichia coli

2011 ◽  
Vol 42 (4) ◽  
pp. 1390-1396 ◽  
Author(s):  
Michelle Rossana Ferreira Vaz ◽  
Ricardo Luiz Soares de França ◽  
Sirtys Santos Lessa de Andrade ◽  
Francisco Canindé de Sousa Junior ◽  
Everaldo Silvino dos Santos ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Culture Medium ◽  
Recombinant Escherichia Coli ◽  
Leishmania Chagasi
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