ISOLATION OF 4-AMINO-5-IMIDAZOLECARBOXAMIDE RIBOSIDE FROM THE CULTURE MEDIUM OF SULFONAMIDE-INHIBITED ESCHERICHIA COLI

1952 ◽  
Vol 74 (24) ◽  
pp. 6307-6308 ◽  
Author(s):  
G. Robert Greenberg
2011 ◽  
Vol 175-176 ◽  
pp. 192-196 ◽  
Author(s):  
Li Li Feng ◽  
Jian Fei Zhang ◽  
Hui Luo ◽  
Zheng Li ◽  
Hong Jie Zhang

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.


2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
F Du ◽  
R Li ◽  
Q Zhang ◽  
W Wang

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


1964 ◽  
Vol 17 (3) ◽  
pp. 719 ◽  
Author(s):  
CI Davern

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.


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

Diseases ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 11 ◽  
Author(s):  
Shane Whelan ◽  
Mary Claire O’Grady ◽  
Dan Corcoran ◽  
Karen Finn ◽  
Brigid Lucey

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.


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 ◽  
...  

1961 ◽  
Vol 39 (10) ◽  
pp. 1551-1558 ◽  
Author(s):  
A. J. Finlayson ◽  
F. J. Simpson

When 2,6-diaminopimelicacid-1,7-C14was added to growing cultures of Bacillus megaterium, Staphlococcus aureus, and Escherichia coli, 8–9% of added carbon-14 appeared in the cellular lysine. Similar experiments with Proteus vulgaris, Streptomyces griseus, Aspergillus flavus, and Lactobacillus arabinosus resulted in less than 0.3% of the added carbon-14 being incorporated into the cellular lysine. Leuconostoc mesenteroides converted 0.6% of the added DAP-1,7-C14to lysine-1-C14.Over 90% of the carbon-14 in cell lysine from B. megaterium and L. mesenteroides was found in the carboxyl carbon. This was interpreted as indicating a direct decarboxylation of DAP-1,7-C14to lysine-1-C14. About 70% of the carbon-14 in the lysine from cells of S. aureus and E. coli was found in the carboxyl carbon, thus suggesting that some lysine comes from sources other than 2,6-diaminopimelic acid.Those organisms that actively decarboxylated DAP-1,7-C14to form lysine-C14also synthesized DAP and excreted it into the culture medium during growth.


2014 ◽  
Vol 65 (3) ◽  
pp. 1607-1613 ◽  
Author(s):  
Michelle Rossana Ferreira Vaz ◽  
Francisco Canindé de Sousa Junior ◽  
Letícia Maia Resende Costa ◽  
Everaldo Silvino dos Santos ◽  
Daniella Regina Arantes Martins ◽  
...  

1994 ◽  
Vol 302 (2) ◽  
pp. 535-538 ◽  
Author(s):  
J Alvarez-Bravo ◽  
S Kurata ◽  
S Natori

Previously, we identified a core undecapeptide of sapecin B having antimicrobial activity. Based on the structure of this peptide, we systematically synthesized peptides consisting of terminal basic motifs and internal oligo-leucine sequences and examined their antimicrobial activities. Of these peptides, RLKLLLLLRLK-NH2 and KLKLLLLLKLK-NH2 were found to have potent microbicidal activity against Staphylococcus aureus, Escherichia coli, methicillin-resistant S. aureus and Candida albicans in liquid medium. We also synthesized the D-enantiomer of KLKLLLLLKLK-NH2. This enantiomer was resistant to tryptic digestion and persisted longer in the culture medium, showing greater antimicrobial activity than the original peptide.


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