Search results for "Escher"

Antibacterial activity of Mediterranean Oyster mushrooms, species of genus Pleurotus (higher Basidiomycetes).

2013

Extracts of the Mediterranean culinary-medicinal Oyster mushrooms Pleurotus eryngii var. eryngii, P. eryngii var. ferulae, P. eryngii var. elaeoselini, and P. nebrodensis were tested for their in vitro growth inhibitory activity against a group of bacterial reference strains of medical relevance: Staphylococcus aureus ATCC 25923, S. epidermidis RP62A, Pseudomonas aeruginosa ATCC 15442, and Escherichia coli ATCC10536. All of the Pleurotus species analyzed inhibited the tested microorganisms in varying degrees. The data included in this paper for P. nebrodensis and P. eryngii var. elaeoselinii are new reports.

The cytoplasmic PASC domain of the sensor kinase DcuS of Escherichia coli : role in signal transduction, dimer formation, and DctA interaction

2013

The cytoplasmic PAS(C) domain of the fumarate responsive sensor kinase DcuS of Escherichia coli links the transmembrane to the kinase domain. PAS(C) is also required for interaction with the transporter DctA serving as a cosensor of DcuS. Earlier studies suggested that PAS(C) functions as a hinge and transmits the signal to the kinase. Reorganizing the PAS(C) dimer interaction and, independently, removal of DctA, converts DcuS to the constitutive ON state (active without fumarate stimulation). ON mutants were categorized with respect to these two biophysical interactions and the functional state of DcuS: type I-ON mutations grossly reorganize the homodimer, and decrease interaction with Dct…

The stability and functional properties of proteoliposomes mixed with dextran derivatives bearing hydrophobic anchor groups

1992

Liposomes composed of Escherichia coli phospholipid were coated with polysaccharides bearing hydrophobic palmitoyl anchors. The effect on the stability of liposomes without or with integral membrane proteins was investigated. A high concentration of hydrophobized dextrans protected the liposomes against detergent degradation, decreased the fluidity of the membranes, prevented fusion of the liposomes and enhanced their stability. Proteoliposomes containing beef heart cytochrome-c oxidase and the lactose transport carrier of E. coli were similarly affected by coating with the dextrans. Under these conditions both membrane proteins were still active. Long-term stability of the coated liposomes…

Confocal laser endomicroscopy is a new imaging modality for recognition of intramucosal bacteria in inflammatory bowel disease in vivo.

2011

International audience; BACKGROUND AND OBJECTIVES: Interaction of bacteria with the immune system within the intestinal mucosa plays a key role in the pathogenesis of inflammatory bowel disease (IBD). The aim of the current study was to develop a fluorescein-aided confocal laser endomicroscopy (CLE) method to visualise intramucosal enteric bacteria in vivo and to determine the involved mucosal area in the colon and ileum in patients with ulcerative colitis (UC) and Crohn's disease (CD). METHODS: Initially, E coli strains expressing enhanced green fluorescent protein (pEGFP) were endomicroscopically imaged in mice. In addition, ex vivo and in vivo imaging of fluorescent human enteric bacteri…

Surface Components of Escherichia coli That Mediate Resistance to the Bactericidal Activities of Serum and Phagocytes

1985

Microorganisms that enter the animal body, either actively or passively, encounter a battery of nonspecific and specific chemical and cellular defenses whose role is to inactivate and eliminate foreign materials. Successful pathogens have the ability to avoid, resist, or inactivate these defenses for at least the period necessary for initiation of the disease process.

One-step synthesis, crystallographic studies and antimicrobial activity of new 4-diazopyrazole derivatives

1996

Summary A number of new 4-diazopyrazole derivatives were prepared by the reaction of 1- R -3-methyl-5(R 1 -substituted)benzamidopyrazoles with a sevenfold excess of nitrous acid in acetic medium. The compounds were tested for activity against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus faecalis, Listeria monocytogenes, Candida albicans, Candida tropicalis and Paecilomyces varioti . The highest microbial susceptibility was shown by Gram-positive bacteria, with minimum inhibitory concentrations (MIC) in the range 0.5–12.5 μg/mL. For S aureus the R 1 substituents were screened utilizing the Topliss operational scheme. The 4-nitro g…

TiO2 Supported over Hβ and HZSM-5 Photocatalysts for Salmonelle and Escherichia Coli Disinfection

2008

Functioning of DcuC as the C 4 -Dicarboxylate Carrier during Glucose Fermentation by Escherichia coli

1999

ABSTRACT The dcuC gene of Escherichia coli encodes an alternative C 4 -dicarboxylate carrier (DcuC) with low transport activity. The expression of dcuC was investigated. dcuC was expressed only under anaerobic conditions; nitrate and fumarate caused slight repression and stimulation of expression, respectively. Anaerobic induction depended mainly on the transcriptional regulator FNR. Fumarate stimulation was independent of the fumarate response regulator DcuR. The expression of dcuC was not significantly inhibited by glucose, assigning a role to DcuC during glucose fermentation. The inactivation of dcuC increased fumarate-succinate exchange and fumarate uptake by DcuA and DcuB, suggesting a…

Regulation of aerobic and anaerobic D-malate metabolism of Escherichia coli by the LysR-type regulator DmlR (YeaT).

2010

ABSTRACT Escherichia coli K-12 is able to grow under aerobic conditions on d -malate using DctA for d -malate uptake and the d -malate dehydrogenase DmlA (formerly YeaU) for converting d -malate to pyruvate. Induction of dmlA encoding DmlA required an intact dmlR (formerly yeaT ) gene, which encodes DmlR, a LysR-type transcriptional regulator. Induction of dmlA by DmlR required the presence of d -malate or l - or meso -tartrate, but only d -malate supported aerobic growth. The regulator of general C 4 -dicarboxylate metabolism (DcuS-DcuR two-component system) had some effect on dmlA expression. The anaerobic l -tartrate regulator TtdR or the oxygen sensors ArcB-ArcA and FNR did not have a m…

Thermostability of Two Cyanobacterial GrpE Thermosensors

2011

GrpE proteins act as co-chaperones for DnaK heat-shock proteins. The dimeric protein unfolds under heat stress conditions, which results in impaired interaction with a DnaK protein. Since interaction of GrpE with DnaK is crucial for the DnaK chaperone activity, GrpE proteins act as a thermosensor in bacteria. Here we have analyzed the thermostability and function of two GrpE homologs of the mesophilic cyanobacterium Synechocystis sp. PCC 6803 and of the thermophilic cyanobacterium Thermosynechococcus elongatus BP1. While in Synechocystis an N-terminal helix pair of the GrpE dimer appears to be the thermosensing domain and mainly mediates GrpE dimerization, the C-terminal four-helix bundle i…