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Escherichia
Published in Dongyou Liu, Laboratory Models for Foodborne Infections, 2017
E. coli is a rod-shaped bacterium of about 0.6 μm in diameter and 2 μm in length. The bacterium forms nonspreading black colonies with a characteristic greenish-black metallic sheen on eosin methylene blue (EMB) agar, and deep red colonies on MacConkey agar. Other morphological features of note include:
The Postnatal Leptin Surge Supports Immune Cell Function in Rats
Published in Immunological Investigations, 2022
Caroline Hunsche, Oskarina Hernandez, Virginia Mela, M. Paz Viveros, Mónica De la Fuente
Chemotaxis of leukocytes was evaluated according to a slight modification of Boyden´s method (De la Fuente et al. 2004). It consisted of the use of chambers with two compartments separated by a nitrocellulose filter with a pore diameter of 3 µm (Millipore, Bedford, MA, USA). Aliquots of 300 μl of the leukocyte suspensions, adjusted to 5 × 105 cells/ml in Hank´s solution, were deposited in the upper compartment, and aliquots of 400 µl of the chemoattractant, formyl-Met-Leu-Phe (10−8 M) (Sigma-Aldrich), were put into the lower compartment. The chambers were incubated at 37°C in a humidified atmosphere of 5% CO2 for 3 h. After the incubation, the filters were removed, fixed, and stained as follows: (1) 50% methanol for 4 min; (2) 75% ethanol for 4 min; (3) distilled water for 2 min; (4) Giemsa´s azur eosin methylene blue solution for 45 min; (5) gently washed with distilled water and dried. The chemotaxis index (CI) was determined by counting, in an optical microscope (100X), the total number of leukocytes on one third of the lower face of the filters.
Mycobacterial ethambutol responsive genes and implications in antibiotics resistance
Published in Journal of Drug Targeting, 2021
Xiaohong Xiang, Zhen Gong, Wanyan Deng, Qingyu Sun, Jianping Xie
Both EMB antimicrobial capacity and the emergence of drug-resistance can be examined by pharmacokinetic–pharmacodynamic PK/PD approaches [9,13,14]. HIV coinfection can affect the concentrations of rifampin (RFP) and EMB and absorption [10,14,15]. The side-effect of EMB includes the performance for optic neuritis, anaphylaxis, mental confusion, anorexia, dermatitis and pruritus, abdominal pain and joint pain, nausea, vomiting, peripheral neuropathy, headache, fever and dizziness [16,17]. The exact mechanism of ocular neurotoxic effect is poorly understood. Studies show that there are four possible reasons: (1) one of the principal theories for its toxicity is due to the divalent metal ions in vivo and its excessive chelating metabolites by EMB, such as zinc-chelating effect of EMB and the side-effect of its metabolite [18,19]. (2) EMB can induce reduction of calcium ion concentration in cytosol, with an increasing concentration of calcium in mitochondria, result in the increasing mitochondrial membrane potential. In addition, ganglion cells are sensitive to normally tolerated levels of extracellular glutamate, the mechanism probably related to the decreased ATPase activity and mitochondrial energy homeostasis. (3) EMB induced the formation of cytoplasmic vacuolar and loss neuron in rat retinal cell culture [20]. (4) EMB may have a toxic effect on retinal pigment epithelium (RPE) including repressing cell growth and reducing phagocytic functions via PKC (protein kinase C) signal pathway [21].
Genomic characterization of four Escherichia coli strains isolated from oral lichen planus biopsies
Published in Journal of Oral Microbiology, 2021
Huitae Min, Keumjin Baek, Ahreum Lee, Yeong-Jae Seok, Youngnim Choi
Although there is a possibility that E. coli colonizing the oral mucosa of healthy subjects are genetically different from the OLP-isolated strains, the OLP strains are more likely to be commensals but increase virulence in the altered environment of OLP patients. Isolation of E. coli strains from the oral mucosa of healthy individuals will clarify this issue. Despite the presence of lacZ, lacY, and lacA genes, the OLP-isolated strains did not form purple-black colonies on a selective and differential medium, such as eosin methylene blue agar. Because E. coli was substantially enriched within the OLP tissues (up to 60%), it was possible to isolate E. coli without colour differentiation. In the buccal swabs of healthy subjects where E. coli accounts for 0.03–7% of total bacteria, however, other Gram-negative species such as Haemophilus spp., Neisseria spp., and Lautropia mirabilis, but not E. coli, have been isolated from cultures on the eosin methylene blue agar.