scholarly journals ccrAB Ent serine recombinase genes are widely distributed in the Enterococcus faecium and Enterococcus casseliflavus species groups and are expressed in E. faecium

Microbiology ◽  
2010 ◽  
Vol 156 (12) ◽  
pp. 3624-3634 ◽  
Author(s):  
Eva Katrin Bjørkeng ◽  
Girum Tadesse Tessema ◽  
Eirik Wasmuth Lundblad ◽  
Patrick Butaye ◽  
Rob Willems ◽  
...  
Keyword(s):  
Enterococcus Faecium ◽  
Constitutive Expression ◽  
Mrna Levels ◽  
Genes Expression ◽  
Chromosomal Genes ◽  
Enterococcus Casseliflavus ◽  
Enterococcal Species ◽  
Species Groups ◽  
Enterococcus Gallinarum ◽  
Sequence Types

The presence, distribution and expression of cassette chromosome recombinase (ccr) genes, which are homologous to the staphylococcal ccrAB genes and are designated ccrAB Ent genes, were examined in enterococcal isolates (n=421) representing 13 different species. A total of 118 (28 %) isolates were positive for ccrAB Ent genes by PCR, and a number of these were confirmed by Southern hybridization with a ccrA Ent probe (n=76) and partial DNA sequencing of ccrA Ent and ccrB Ent genes (n=38). ccrAB Ent genes were present in Enterococcus faecium (58/216, 27 %), Enterococcus durans (31/38, 82 %), Enterococcus hirae (27/52, 50 %), Enterococcus casseliflavus (1/4, 25 %) and Enterococcus gallinarum (1/2, 50 %). In the eight other species tested, including Enterococcus faecalis (n=94), ccrAB Ent genes were not found. Thirty-eight sequenced ccrAB Ent genes from five different enterococcal species showed 94–100 % nucleotide sequence identity and linkage PCRs showed heterogeneity in the ccrAB Ent flanking chromosomal genes. Expression analysis of ccrAB Ent genes from the E. faecium DO strain showed constitutive expression as a bicistronic mRNA. The ccrAB Ent mRNA levels were lower during log phase than stationary phase in relation to total mRNA. Multilocus sequence typing was performed on 39 isolates. ccrAB Ent genes were detected in both hospital-related (10/29, 34 %) and non-hospital (4/10, 40 %) strains of E. faecium. Various sequence types were represented by both ccrAB Ent positive and negative isolates, suggesting acquisition or loss of ccrAB Ent in E. faecium. In summary, ccrAB Ent genes, potentially involved in genome plasticity, are expressed in E. faecium and are widely distributed in the E. faecium and E. casseliflavus species groups.

scholarly journals Effects of Different Test Conditions on MICs of Food Animal Growth-Promoting Antibacterial Agents for Enterococci

1998 ◽  
Vol 36 (7) ◽  
pp. 1907-1911 ◽  
Author(s):  
Patrick Butaye ◽  
Luc A. Devriese ◽  
Freddy Haesebrouck
Keyword(s):  
Aerobic Incubation ◽  
Mueller Hinton ◽  
Enterococcus Mundtii ◽  
Enterococcus Casseliflavus ◽  
Enterococcal Species ◽  
Animal Growth ◽  
Growth Promoting ◽  
Enterococcus Gallinarum ◽  
Susceptibility Tests ◽  
Free Media

The influence of the addition of sheep blood to Mueller-Hinton II agar and the effects of aerobic incubation with or without CO2 and of anaerobic incubation were tested with bacitracin, tylosin, avoparcin, virginiamycin, avilamycin, narasin, and flavomycin on enterococci. The antibacterial activity of bambermycin (Flavomycin) was strongly inhibited by the addition of blood, except with the species Enterococcus faecium, Enterococcus mundtii, Enterococcus hirae, Enterococcus casseliflavus, and Enterococcus gallinarum, which were not susceptible to this antibiotic on blood-free medium. With all other antimicrobials except avoparcin and tylosin, the presence of blood resulted in MIC increases of 1 to 3 log2 differences. Incubation in aerobic or anaerobic atmospheres enriched with CO2 lowered the susceptibility of enterococci to tylosin and increased their susceptibility to avilamycin, narasin, and avoparcin. This effect was most pronounced in tests on blood-free media. Results of susceptibility tests incubated under anaerobiosis and in a CO2-enriched atmosphere did not differ. For all enterococcal species, the preferred conditions for testing the susceptibility are Mueller-Hinton II medium supplemented with blood and incubation in a CO2-enriched atmosphere. However, when onlyE. faecium and Enterococcus faecalis are being tested, Mueller-Hinton II medium without blood incubated aerobically gives satisfactory results.

scholarly journals Use of Tests for Acidification of Methyl-α-d-Glucopyranoside and Susceptibility to Efrotomycin for Differentiation of Strains ofEnterococcus and Some Related Genera

1998 ◽  
Vol 36 (6) ◽  
pp. 1584-1587 ◽  
Author(s):  
Maria Da Glória S. Carvalho ◽  
Lúcia M. Teixeira ◽  
Richard R. Facklam
Keyword(s):  
Enterococcus Faecalis ◽  
Enterococcus Faecium ◽  
Clinical Microbiology ◽  
Clinical Microbiology Laboratory ◽  
Microbiology Laboratory ◽  
Lactococcus Garvieae ◽  
Negative Results ◽  
Enterococcus Casseliflavus ◽  
Enterococcus Gallinarum ◽  
Atypical Strains

A total of 107 Enterococcus strains, 10Vagococcus fluvialis strains, and 8 Lactococcus garvieae strains were tested for acidification of methyl-α-d-glucopyranoside (MGP) and susceptibility to 100-μg efrotomycin (EFRO) disks. All 26 strains ofEnterococcus casseliflavus, including 3 nonmotile and 2 nonpigmented strains, acidified MGP and were resistant to EFRO. All 22 strains of Enterococcus gallinarum, including 5 nonmotile strains, also acidified MGP and were resistant to EFRO. None of the 26 strains of Enterococcus faecium acidified MGP, and all were susceptible to EFRO. Although all 12 Enterococcus faecalisstrains were also negative in the MGP test, they were resistant to EFRO. Other enterococcal strains gave variable results. All 10 strains of V. fluvialis and all 8 strains of L. garvieae gave positive and negative results, respectively, in the MGP test and were, respectively, resistant and susceptible to EFRO. These results indicate that tests of the production of acid from MGP and susceptibility to EFRO can be used as adjunct tests in the identification of typical and atypical strains of enterococci in the clinical microbiology laboratory.

scholarly journals Comparison of Simple and Rapid Methods for Identifying Enterococci Intrinsically Resistant to Vancomycin

1999 ◽  
Vol 37 (3) ◽  
pp. 815-817 ◽  
Author(s):  
Kevan L. Hanson ◽  
Charles P. Cartwright
Keyword(s):  
Enterococcus Faecalis ◽  
Enterococcus Faecium ◽  
Rapid Methods ◽  
Vancomycin Resistant Enterococci ◽  
Litmus Milk ◽  
Overnight Incubation ◽  
Enterococcus Casseliflavus ◽  
Vancomycin Resistant ◽  
Enterococcus Gallinarum

Three different methodologies, reduction of litmus milk (LM) and acidification of arabinose (ARA), acidification of methyl-α-d-glucopyranoside (MGP), and rapid motility (RM), for differentiating isolates of Enterococcus casseliflavus and Enterococcus gallinarum(intrinsically vancomycin-resistant enterococci [IVRE]) fromEnterococcus faecalis and Enterococcus faeciumwere evaluated. All 33 isolates of E. faecalis tested reduced LM within 4 h and were negative in all other tests, while the 53 isolates of E. faecium were ARA positive only. In contrast, 45 of 46 (98%) IVRE isolates examined (26 E. casseliflavus and 20 E. gallinarum isolates) acidified MGP, 41 of 46 (89%) were LM and ARA positive, and 45 of 46 (98%) were RM positive. Acidification of MGP was therefore the single most useful test for differentiating IVRE from vancomycin-resistantE. faecium and E. faecalis; however, a combination of LM-ARA and RM testing enabled the correct designation of organisms without the need for overnight incubation.

The Dominant Sequence Types of Vancomycin-Resistant Enterococcus faecium Among Transplantation Ward Patients

2011 ◽  
Vol 43 (8) ◽  
pp. 3132-3134 ◽  
Author(s):  
A. Mlynarczyk ◽  
K. Szymanek-Majchrzak ◽  
E. Kosykowska ◽  
W. Grzybowska ◽  
S. Tyski ◽  
...  
Keyword(s):  
Enterococcus Faecium ◽  
Vancomycin Resistant Enterococcus ◽  
Vancomycin Resistant ◽  
Sequence Types

Expression of the Saccharomyces cerevisiae GAL7 gene on autonomous plasmids

1984 ◽  
Vol 4 (10) ◽  
pp. 2062-2071
Author(s):  
S M Baker ◽  
P G Okkema ◽  
J A Jaehning
Keyword(s):  
Gene Dosage ◽  
Constitutive Expression ◽  
Single Copy ◽  
Initial Time ◽  
Sufficient Information ◽  
Mrna Levels ◽  
Dna Encoding ◽  
Yeast Plasmid ◽  
Regulatory Factors

We used a combination of cloned DNA fragments encoding the GAL7 gene, yeast plasmid vectors, and chromosomal gal7 deletions to characterize the in vivo transcription of the GAL7 gene on autonomously replicating plasmids. Our results demonstrated that a plasmid-borne 3.1-kilobase DNA fragment containing the GAL7 gene provides sufficient information to mimic the regulated expression of the chromosomal location. Normal expression of GAL7 could occur in the absence of DNA encoding the functional genes of the GAL cluster region and was not altered when the gene was adjacent to other plasmid elements such as autonomously replicating sequences or centromeres. The chromosomal and single-copy centromeric plasmid locations of GAL7 were indistinguishable in their response to growth conditions (induction by galactose, repression by glucose) and positive and negative regulatory factors (GAL4 and GAL80). Increasing the gene dosage to more than 200 copies per cell resulted in constitutive expression of the GAL7 mRNA; fully induced mRNA levels were increased more than 10-fold at these high gene dosages. When cells were shifted from noninducing to inducing conditions, the initial time of appearance and the rate of accumulation of GAL7 mRNA were altered in cell populations containing multiple GAL7 genes. The induction kinetics and final accumulation of the chromosomal GAL10 mRNA were also affected by the presence of multiple copies of the GAL7 gene; these results are consistent with a model involving limiting amounts of regulatory factors.

scholarly journals Human mononuclear cells express 12-LX: coordinated mRNA regulation with 5-LX and FLAP genes

Blood ◽  
1996 ◽  
Vol 87 (1) ◽  
pp. 331-340
Author(s):  
WE Kaminski ◽  
E Jendraschak ◽  
K Baumann ◽  
R Kiefl ◽  
S Fischer ◽  
...  
Keyword(s):  
Gene Expression ◽  
Mrna Expression ◽  
Time Course ◽  
Cell Activation ◽  
Mononuclear Cells ◽  
Constitutive Expression ◽  
Ionophore A23187 ◽  
Mrna Levels ◽  
Rt Pcr ◽  
Human Mononuclear Cells

Lipoxygenases (LXs) catalyze formation of leukotrienes and hydroxy-eicosatetraenoic acids (HETEs), proinflammatory, and spasmogenic autacoids that are critical for host defense systems. We studied the expression and regulation of LX genes (12-LX, 5-LX, and 15-LX) and the 5-lipoxygenase activating protein (FLAP) in human mononuclear cells (MNC) and granulocytes using a quantitative reverse transcription polymerase chain reaction (RT-PCR) technique. We show that 12-LX mRNA is constitutively expressed in resting platelet-free MNC. 12-LX gene expression was upregulated by activation with lipopolysaccharide (LPS). The formation of 12-HETE was inducible with ionophore in MNC, as assessed by high-performance liquid chromatography (HPLC) and gas chromatography, and increased after LPS pretreatment. In addition to 12- LX, resting MNC expressed the genes for 5-LX and FLAP constitutively. Quantitative time course analyses of 12-LX, 5-LX, and FLAP gene expression suggested coregulation of 12-LX and FLAP mRNAs, and reciprocal regulation of 5-LX and FLAP mRNAs. During cell stimulation with LPS 5-LX mRNA levels remained unchanged, whereas FLAP gene expression increased. No 15-LX mRNA expression or 15-HETE formation was detectable in unstimulated and activated MNC. In contrast to MNC, quantitative RT-PCR mRNA analysis showed intermittent intraindividual expression of the 5-LX and FLAP genes in resting granulocytes. mRNAs for 12-LX and 15-LX were not expressed. On stimulation of granulocytes ex vivo, mRNA expression of 5-LX and FLAP was upregulated. Stimulation by LPS differed from that by ionophore A23187. Neither LPS nor ionophore induced gene expression of 12-LX or 15-LX in granulocytes. Our data indicate that resting human MNC and granulocytes express LX and FLAP genes in a cell-specific manner. Cell activation induces coordinated upregulation of 12-LX and FLAP genes in MNC, and 5-LX and FLAP genes in granulocytes, respectively. The constitutive expression of 12-LX mRNA, its upregulation on cell activation, and the formation of 12-HETE clearly indicate the presence of a functional 12-LX in human MNC.

Repression of cyclin D1: a novel function of MYC

1994 ◽  
Vol 14 (6) ◽  
pp. 4032-4043
Author(s):  
A Philipp ◽  
A Schneider ◽  
I Väsrik ◽  
K Finke ◽  
Y Xiong ◽  
...  
Keyword(s):  
Cyclin D1 ◽  
Transcription Initiation ◽  
Core Promoter ◽  
Constitutive Expression ◽  
Mrna Levels ◽  
Amino Terminal ◽  
3T3 Fibroblasts ◽  
Tata Element

Constitutive expression of human MYC represses mRNA levels of cyclin D1 in proliferating BALB/c-3T3 fibroblasts. We expressed a series of mutant alleles of MYC and found that downregulation of cyclin D1 is distinct from previously described properties of MYC. In particular, we found that association with Max is not required for repression of cyclin D1 by MYC in vivo. Conversely, the integrity of a small amino-terminal region (amino acids 92 to 106) of MYC is critical for repression of cyclin D1 but dispensable for transformation of established RAT1A cells. Runoff transcription assays showed that repression occurs at the level of transcription initiation. We cloned the promoter of the gene for human cyclin D1 and found that it lacks a canonical TATA element. Transcription starts at an initiator element similar to that of the adenovirus major late promoter; this element can be directly bound by USF in vitro. Expression of MYC represses the cyclin D1 promoter via core promoter elements and antagonizes USF-mediated transactivation. Taken together, our data define a new pathway for gene regulation by MYC and show that the cyclin D1 gene is a target gene for repression by MYC.

Cell cycle regulation of a mouse histone H4 gene requires the H4 promoter

1987 ◽  
Vol 7 (3) ◽  
pp. 1048-1054
Author(s):  
A Seiler-Tuyns ◽  
B M Paterson
Keyword(s):  
Cell Cycle ◽  
Shuttle Vector ◽  
Constitutive Expression ◽  
Mrna Levels ◽  
Histone H4 ◽  
Coding Region ◽  
Regulated Expression ◽  
Arrest Growth ◽  
Globin Promoter ◽  
Histone H4 Gene

The mouse histone H4 gene, when stably transformed into L cells on the PSV2gpt shuttle vector, is cell cycle regulated in parallel with the endogenous H4 genes. This was determined in exponentially growing pools of transformants fractionated into cell cycle-specific stages by centrifugal elutriation, a method for purifying cells at each stage of the cell cycle without the use of treatments that arrest growth. Linker additions in the 5' noncoding region of the H4 RNA or in the coding region of the gene did not affect the cell cycle-regulated expression of the modified H4 gene even though the overall level of expression was altered. However, replacing the H4 promoter with the human alpha-2 globin promoter, so that the histone transcript produced by the chimeric gene remains essentially unchanged, resulted in the constitutive expression of H4 mRNA during all phases of the cell cycle with no net increase in H4 mRNA levels during the G1-to-S transition. From these results we conclude that all the information necessary for the cell cycle-regulated expression of the H4 gene is contained in the 5.2-kilobase subclone used in these studies with 228 nucleotides of 5'-flanking DNA and that the increase in H4 mRNA during the G1-to-S transition in the cell cycle is mediated by the H4 promoter and not by the increased stability of the H4 RNA.

Regulation of macrophage colony-stimulating factor in liver fat-storing cells by peptide growth factors

1992 ◽  
Vol 262 (4) ◽  
pp. C876-C881 ◽  
Author(s):  
M. Pinzani ◽  
H. E. Abboud ◽  
L. Gesualdo ◽  
S. L. Abboud
Keyword(s):  
Growth Factor ◽  
Constitutive Expression ◽  
Liver Fat ◽  
Northern Analysis ◽  
Mrna Levels ◽  
Colony Stimulating Factor ◽  
Term Survival ◽  
Macrophage Colony Stimulating Factor ◽  
Macrophage Colony ◽  
Stimulating Factor

Macrophage colony-stimulating factor (M-CSF) selectively promotes mononuclear phagocyte survival, proliferation, and differentiation. The production of this factor within the liver may be necessary to support the relatively long-term survival of circulating monocytes as they migrate into tissues and differentiate into macrophages. We studied the constitutive expression and the effects of platelet-derived growth factor (PDGF), basic fibroblast growth factor (bFGF), and epidermal growth factor (EGF) on M-CSF mRNA levels and secretion of M-CSF in murine liver fat-storing cells (FSC), vascular pericytes likely involved in the development of liver fibrosis. By Northern analysis, using a murine M-CSF cDNA, FSC constitutively express two major transcripts of 4.4 and 2.2 kb, similar to those detected in mouse L cells, used as a control. Exposure to 10 ng/ml PDGF or bFGF increased M-CSF mRNA levels. Peak effects were observed at 3 and 6 h for PDGF and bFGF, respectively, returning to baseline levels by 12 h. Under basal conditions, detectable amounts of M-CSF, measured by radioimmunoassay, were found in cell supernatants conditioned for 8 and 24 h. PDGF and bFGF markedly stimulated the release of M-CSF as early as 8 h, an effect persisting for at least 24 h. These findings suggest that liver FSC release M-CSF upon stimulation by PDGF and bFGF and may contribute to the activation of resident or infiltrating cells in inflammatory liver diseases.

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