In vivo and in vitro biosynthesis of free fatty alcohols inEscherichia Coli K-12

Lipids ◽  
1974 ◽  
Vol 9 (6) ◽  
pp. 419-428 ◽  
Author(s):  
William F. Naccarato ◽  
John R. Gilbertson ◽  
Rose A. Gelman
Keyword(s):  
Fatty Alcohols ◽  
Inescherichia Coli ◽  
In Vitro Biosynthesis ◽  
K 12

Biochemical and pharmacokinetic characterisation of two PEGylated variants of dipetarudin

2009 ◽  
Vol 102 (09) ◽  
pp. 454-459 ◽  
Author(s):  
Anne Koehler ◽  
Goetz Nowak ◽  
Mercedes López
Keyword(s):  
Gel Filtration ◽  
Pharmacokinetic Profile ◽  
Peripheral Compartment ◽  
Therapeutic Application ◽  
Similar Activity ◽  
Elimination Half ◽  
K 12 ◽  
Extravascular Compartment

SummaryDipetarudin was coupled to polyethylene glycol (PEG)-5000 residues in order to improve its pharmacokinetic profile and to enhance its anticoagulant efficacy. The resulting compounds, mono-and di-PEGylated dipetarudin were purified by gel filtration. Mono-PEGylated dipetarudin exhibited similar activity like its non-conjugated equivalent both in vitro and in vivo. However, di-PEGylated dipetarudin showed longer distribution and elimination half-lives and higher area under the time-concentration curve in comparison with the unmodified inhibitor which may be attributed to decreased renal clearance. Futhermore, ratio k 12/k 21 decreased when the number of PEG chains coupled to dipetarudin increased. It means that the intercompartment transfer of dipetarudin, characterised by a fast distribution and a high retention in the peripheral compartment, is reverted by coupling to PEG. Thus, the transfer of mono-PEGylated dipetarudin between these compartments is similar in both senses and the transfer of di-PEGylated dipetarudin is slower from vascular to extravascular compartment than vice versa. Our results show that di-PEGylated dipetarudin produces a better and longer anticoagulant effect than unmodified dipetarudin which is a desirable attribute for future therapeutic application.

scholarly journals Identification of Escherichia coli Genes That Are Specifically Expressed in a Murine Model of Septicemic Infection

2002 ◽  
Vol 70 (7) ◽  
pp. 3404-3412 ◽  
Author(s):  
Muhammad A. Khan ◽  
Richard E. Isaacson
Keyword(s):  
Escherichia Coli ◽  
Dna Sequences ◽  
Anaerobic Respiration ◽  
Disease Process ◽  
Antimicrobial Drugs ◽  
Reverse Transcription Pcr ◽  
Successful Infection ◽  
K 12

ABSTRACT Identification and characterization of bacterial genes that are induced during the disease process are important in understanding the molecular mechanism of disease and can be useful in designing antimicrobial drugs to control the disease. The identification of in vivo induced (ivi) genes of an Escherichia coli septicemia strain by using antibiotic-based in vivo expression technology is described. Bacterial clones resistant to chloramphenicol in vivo were recovered from the livers of infected mice. Most of the ivi clones were sensitive to chloramphenicol when grown in vitro. Using reverse transcription-PCR, it was demonstrated that selected ivi clones expressed cat in the livers of infected mice but not during in vitro growth. A total of 750 colonies were recovered after three successive rounds of in vivo selection, and 168 isolated ivi clones were sequenced. The sequence analysis revealed that 37 clones encoded hypothetical proteins found in E. coli K-12, whereas 10 clones contained genes that had no significant homology to DNA sequences in GenBank. Two clones were found to contain transposon-related functions. Other clones contained genes required for amino acid metabolism, anaerobic respiration, DNA repair, the heat shock response, and the cellular repressor of the SOS response. In addition, one clone contained the aerobactin biosynthesis gene iucA. Mutations were introduced in to seven of the identified ivi genes. An in vivo mouse challenge-competition assay was used to determine if the mutants were attenuated. The results suggested that these ivi genes were important for survival in vivo, and three of the seven mutant ivi clones were required for successful infection of mice.

Phosphorylierung von Methylthio-β.ᴅ-galaktosid in E. coli

1968 ◽  
Vol 23 (9) ◽  
pp. 1219-1221 ◽  
Author(s):  
E. Lodemann ◽  
S. Iskrić ◽  
C. Altaner ◽  
A. Wacker
Keyword(s):  
E Coli ◽  
K 12

Methylthio-β.ᴅ-galaktosid wird in E. coli K 12, sowie in den Mutanten ML 3 und ML 308 in vivo zu einem geringen Teil in einen Phosphorsäureester, wahrscheinlich das 6-Phosphat (TMG-P) umgewandelt. TMG-P wird von E. coli K 12 aufgenommen, wirkt jedoch nicht als Induktor des Lactose-Operons. Zellfreie Extrakte aus E. coli K 12 geben die gleiche Reaktion, wobei die in vitro-Reaktion durch anorganisches Phosphat und Phosphoenolpyruvat stimuliert wird.

scholarly journals Regulatory Role of PlaR (YiaJ) for Plant Utilization in Escherichia coli K-12

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Tomohiro Shimada ◽  
Yui Yokoyama ◽  
Takumi Anzai ◽  
Kaneyoshi Yamamoto ◽  
Akira Ishihama
Keyword(s):  
Escherichia Coli ◽  
Genetic System ◽  
Regulatory Role ◽  
E Coli ◽  
Warm Blooded Animal ◽  
Plant Utilization ◽  
K 12

AbstractOutside a warm-blooded animal host, the enterobacterium Escherichia coli K-12 is also able to grow and survive in stressful nature. The major organic substance in nature is plant, but the genetic system of E. coli how to utilize plant-derived materials as nutrients is poorly understood. Here we describe the set of regulatory targets for uncharacterized IclR-family transcription factor YiaJ on the E. coli genome, using gSELEX screening system. Among a total of 18 high-affinity binding targets of YiaJ, the major regulatory target was identified to be the yiaLMNOPQRS operon for utilization of ascorbate from fruits and galacturonate from plant pectin. The targets of YiaJ also include the genes involved in the utilization for other plant-derived materials as nutrients such as fructose, sorbitol, glycerol and fructoselysine. Detailed in vitro and in vivo analyses suggest that L-ascorbate and α-D-galacturonate are the effector ligands for regulation of YiaJ function. These findings altogether indicate that YiaJ plays a major regulatory role in expression of a set of the genes for the utilization of plant-derived materials as nutrients for survival. PlaR was also suggested to play protecting roles of E. coli under stressful environments in nature, including the formation of biofilm. We then propose renaming YiaJ to PlaR (regulator of plant utilization).

scholarly journals Mutational Analysis of Residues in PriA and PriC Affecting Their Ability To Interact with SSB in Escherichia coli K-12

2020 ◽  
Vol 202 (23) ◽  
Author(s):  
Anastasiia N. Klimova ◽  
Steven J. Sandler
Keyword(s):  
Escherichia Coli ◽  
Mutational Analysis ◽  
Wild Type ◽  
Content Type ◽  
Growth Defects ◽  
C Terminus ◽  
K 12 ◽  
And Function

ABSTRACT Escherichia coli PriA and PriC recognize abandoned replication forks and direct reloading of the DnaB replicative helicase onto the lagging-strand template coated with single-stranded DNA-binding protein (SSB). Both PriA and PriC have been shown by biochemical and structural studies to physically interact with the C terminus of SSB. In vitro, these interactions trigger remodeling of the SSB on ssDNA. priA341(R697A) and priC351(R155A) negated the SSB remodeling reaction in vitro. Plasmid-carried priC351(R155A) did not complement priC303::kan, and priA341(R697A) has not yet been tested for complementation. Here, we further studied the SSB-binding pockets of PriA and PriC by placing priA341(R697A), priA344(R697E), priA345(Q701E), and priC351(R155A) on the chromosome and characterizing the mutant strains. All three priA mutants behaved like the wild type. In a ΔpriB strain, the mutations caused modest increases in SOS expression, cell size, and defects in nucleoid partitioning (Par−). Overproduction of SSB partially suppressed these phenotypes for priA341(R697A) and priA344(R697E). The priC351(R155A) mutant behaved as expected: there was no phenotype in a single mutant, and there were severe growth defects when this mutation was combined with ΔpriB. Analysis of the priBC mutant revealed two populations of cells: those with wild-type phenotypes and those that were extremely filamentous and Par− and had high SOS expression. We conclude that in vivo, priC351(R155A) identified an essential residue and function for PriC, that PriA R697 and Q701 are important only in the absence of PriB, and that this region of the protein may have a complicated relationship with SSB. IMPORTANCE Escherichia coli PriA and PriC recruit the replication machinery to a collapsed replication fork after it is repaired and needs to be restarted. In vitro studies suggest that the C terminus of SSB interacts with certain residues in PriA and PriC to recruit those proteins to the repaired fork, where they help remodel it for restart. Here, we placed those mutations on the chromosome and tested the effect of mutating these residues in vivo. The priC mutation completely abolished function. The priA mutations had no effect by themselves. They did, however, display modest phenotypes in a priB-null strain. These phenotypes were partially suppressed by SSB overproduction. These studies give us further insight into the reactions needed for replication restart.

scholarly journals Adaptation in a Mouse Colony Monoassociated with Escherichia coli K-12 for More than 1,000 Days

2010 ◽  
Vol 76 (14) ◽  
pp. 4655-4663 ◽  
Author(s):  
Sean M. Lee ◽  
Aaron Wyse ◽  
Aaron Lesher ◽  
Mary Lou Everett ◽  
Linda Lou ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Growth Rates ◽  
Bacterial Species ◽  
Intestinal Flora ◽  
Average Density ◽  
Host Bacterium ◽  
E Coli ◽  
K 12

ABSTRACT Although mice associated with a single bacterial species have been used to provide a simple model for analysis of host-bacteria relationships, bacteria have been shown to display adaptability when grown in a variety of novel environments. In this study, changes associated with the host-bacterium relationship in mice monoassociated with Escherichia coli K-12 over a period of 1,031 days were evaluated. After 80 days, phenotypic diversification of E. coli was observed, with the colonizing bacteria having a broader distribution of growth rates in the laboratory than the parent E. coli. After 1,031 days, which included three generations of mice and an estimated 20,000 generations of E. coli, the initially homogeneous bacteria colonizing the mice had evolved to have widely different growth rates on agar, a potential decrease in tendency for spontaneous lysis in vivo, and an increased tendency for spontaneous lysis in vitro. Importantly, mice at the end of the experiment were colonized at an average density of bacteria that was more than 3-fold greater than mice colonized on day 80. Evaluation of selected isolates on day 1,031 revealed unique restriction endonuclease patterns and differences between isolates in expression of more than 10% of the proteins identified by two-dimensional electrophoresis, suggesting complex changes underlying the evolution of diversity during the experiment. These results suggest that monoassociated mice might be used as a tool for characterizing niches occupied by the intestinal flora and potentially as a method of targeting the evolution of bacteria for applications in biotechnology.

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