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Entamoeba histolytica
Published in Peter D. Walzer, Robert M. Genta, Parasitic Infections in the Compromised Host, 2020
William A. Petri, Jonathan I. Ravdin
Amebas isolated from patients with amebic dysentery had much higher rates of erythrophagocytosis than strains isolated from healthy human carriers (120, 121). Phagocytic-deficient clones were avirulent as measured by liver abscess formation (122), giving further evidence of the importance of phagocytosis for virulence. Cell lysis is also a virulence factor: The ability of E. histolytica to lyse cell monolayers in vitro has been directly correlated to amebic virulence as measured by liver abscess formation in newborn hamsters (122-124). Analysis of amebic isoenzyme patterns from clinical isolates has shown an association of a phosphoglucomutase isoenzyme ("β band") and hexokinase isoenzyme with invasive strains: All 38 isolates from aspirated human liver abscess but only 3 of 67 isolates from asymptomatic cyst passers had the β band of phosphoglucomutase ("pathogenic zymodeme") (125). Whether or not the phosphoglucomutase isoenzyme pattern remains stable over time and the relationship between the isoenzyme and pathogenicity remain to be established.
Reactivities of Amino Acids and Proteins with Iodine
Published in Erwin Regoeczi, Iodine-Labeled Plasma Proteins, 2019
In phosphoglucomutase, that catalyzes the interconversion of glucose 1-phosphate and glucose 6-phosphate via the intermediate glucose 1,6-biphosphate, the activity is lost on iodination (KI3), nitration, or acetylation of a reactive tyrosyl.352
Receptors and Signal Transduction Pathways Involved in Autonomic Responses
Published in Kenneth J. Broadley, Autonomic Pharmacology, 2017
cAMP serves as a second messenger in many varied physiological events by activating cAMP-dependent protein kinase (PKA). This enzyme exists as a tetramer (R2C2) consisting of two regulatory subunits (R) and two catalytic subunits (C). Two molecules of cAMP bind to each regulatory subunit causing the dissociation of two activated catalytic subunits. These catalyse the phosphorylation of a wide range of proteins, and in glycogenolysis phosphorylase kinase is activated. This enzyme is also partially activated by a rise in intracellular Ca2+ which will accompany increases in cardiac muscle contractility induced by β-adrenoceptor stimulation and hence assist in energy provision. Activated phosphorylase kinase converts phosphorylase b (inactive) to phosphorylase a (active) by phosphorylation of a serine residue (Ser-14). This is the enzyme that controls the rate-limiting step in glycogenolysis, whereby glucose units are removed sequentially, as glucose-1-phosphate, from the glycogen polymer by phosphorolytic cleavage of the α-1,4 linkages. By the action of phosphoglucomutase, this in turn is converted to glucose-6-phosphate, which is utilized as a major energy source in muscles by incorporation into glycolysis pathways with the ultimate generation of ATP and pyruvate.
Stenotrophomonas maltophilia biofilm: its role in infectious diseases
Published in Expert Review of Anti-infective Therapy, 2019
Samantha Flores-Treviño, Paola Bocanegra-Ibarias, Adrián Camacho-Ortiz, Rayo Morfín-Otero, Humberto Antonio Salazar-Sesatty, Elvira Garza-González
Polysaccharides are components of the extracellular matrix of bacterial biofilms that also play a role in resistance to antibiotics [7]. Several gene products are implicated in the formation of the intermediates of LPSs and exopolysaccharides present in the bacterial cell outer membrane, which consequently may be involved in biofilm formation (Table 1). The spgM gene is a homologue of the algC gene, responsible for alginate biosynthesis in Pseudomonas aeruginosa. In S. maltophilia, this gene encodes a bifunctional enzyme with phosphoglucomutase and phosphomannomutase activities involved in LPS production, which contributes to antimicrobial resistance and virulence [15]. The spgM gene renders high biofilm production in both CF and non-CF S. maltophilia strains [16], with high prevalence in these strains (71.6–100%) [16–19].
Neutrophil Functions in Immunodeficiency Due to DOCK8 Deficiency
Published in Immunological Investigations, 2019
Amarilla B. Mandola, Jacov Levy, Amit Nahum, Nurit Hadad, Rachel Levy, Anna Rylova, Amos J. Simon, Atar Lev, Raz Somech, Arnon Broides
There are multiple reports of neutrophil chemotaxis defect in patients with “hyper-IgE syndrome” (Chehimi et al., 2001; Gahr et al., 1987; Galli et al., 1983; Lin et al., 1985; Montoya et al., 2003; Soderberg-Warner et al., 1983; Vargas et al., 1999); however, these studies were performed before the main genetic causes primary immunodeficiency diseases that could possibly be diagnosed as hyper-IgE syndrome became evident: signal transducer and activator of transcription3 (STAT3) mutations in 2007 (Holland et al., 2007; Minegishi et al., 2007; Renner et al., 2007), tyrosine kinase 2 (TYK2) in 2006 (Minegishi et al., 2006), DOCK8 mutations in 2009 (Engelhardt et al., 2009; Zhang et al., 2009) and phosphoglucomutase (PGM3) in 2014 (Zhang et al., 2014). It has been shown that the neutrophil defect in hyper-IgE syndrome patients due to a mutation in STAT3 may be due to a defect in expression of chemoattractant receptors on neutrophils or a chemokine/cytokine abnormality (Mintz et al., 2010) and these patients tend to have abscesses without substantial inflammation (Holland et al., 2007; Minegishi et al., 2007; Renner et al., 2007), suggesting a possible neutrophil function defect. We speculated that some of the “hyper-IgE syndrome” patients included in previous studies on neutrophil chemotaxis and functions were actually patients with a mutation in DOCK8 and therefore we speculated that DOCK8 is expressed in neutrophils and may have a role in neutrophil function.
Anti-elastase and anti-collagenase potential of Lactobacilli exopolysaccharides on human fibroblast
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2018
Mahdieh Shirzad, Javad Hamedi, Elahe Motevaseli, Mohammad Hossein Modarressi
Primary dermal fibroblast was seeded at 5 × 105 cells per well in 6-well plates. Fibroblasts were cultured with 10% FBS and DMEM for 48 h. The cells were synchronized with DMEM without FBS for 7 h. The media were replaced with the same media with 2% FBS and 2 mg of each EPS. After 12 h of treatment, the total RNA was extracted using RiboEx solution (GeneAll), and cDNA was synthesized using 1 μg of the extracted RNA and a PrimeScriptTM RT reagent kit (Takara Bio, Japan)(27). Using SYBR Green Realtime PCR Master Mix and a RG-6000 (Corbett, Australia) real-time PCR machine, the expression levels of MMP genes in the synthesized cDNA were examined. The relevant primers are described in Table 1. MMP1, MMP3 and MMP10 primers were designed by primer-blast of NCBI and evaluated by gene runner ×64. The program used in the examination were 30 s at 95 °C, following 45 cycles of two steps amplification, including 15 s at 95 °C and 30 s at 60 °C (for: MMP1, MMP3, MMP10) or 65 °C (for: TIMP1, TIMP2, MMP2 and MMP9) [38]. The experiments were performed in duplicate for three independent repeats. PGM1 (phosphoglucomutase-1) gene was selected as a normalizer. Melting curve analysis was performed for each primer set.