In vitro mutagenicity, NMR metabolite characterization of azo and triphenylmethanes dyes by adherents bacteria and the role of the “cna” adhesion gene in activated sludge

2017 ◽  
Vol 103 ◽  
pp. 29-39 ◽  
Author(s):  
Lamia Ayed ◽  
Karima Bakir ◽  
Hedi Ben Mansour ◽  
Saousen Hammami ◽  
Abdelkrim Cheref ◽  
...  
Keyword(s):  
Activated Sludge

scholarly journals Characterization of a Dye-Decolorizing Peroxidase from Irpex lacteus Expressed in Escherichia coli: An Enzyme with Wide Substrate Specificity Able to Transform Lignosulfonates

2021 ◽  
Vol 7 (5) ◽  
pp. 325
Author(s):  
Laura Isabel de de Eugenio ◽  
Rosa Peces-Pérez ◽  
Dolores Linde ◽  
Alicia Prieto ◽  
Jorge Barriuso ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Inclusion Bodies ◽  
Veratryl Alcohol ◽  
Dye Decolorization ◽  
Irpex Lacteus ◽  
Type D ◽  
Lignin Peroxidases

A dye-decolorizing peroxidase (DyP) from Irpex lacteus was cloned and heterologously expressed as inclusion bodies in Escherichia coli. The protein was purified in one chromatographic step after its in vitro activation. It was active on ABTS, 2,6-dimethoxyphenol (DMP), and anthraquinoid and azo dyes as reported for other fungal DyPs, but it was also able to oxidize Mn2+ (as manganese peroxidases and versatile peroxidases) and veratryl alcohol (VA) (as lignin peroxidases and versatile peroxidases). This corroborated that I. lacteus DyPs are the only enzymes able to oxidize high redox potential dyes, VA and Mn+2. Phylogenetic analysis grouped this enzyme with other type D-DyPs from basidiomycetes. In addition to its interest for dye decolorization, the results of the transformation of softwood and hardwood lignosulfonates suggest a putative biological role of this enzyme in the degradation of phenolic lignin.

The role of time-lapse fluorescent microscopy in the characterization of toxic effects in cell populations cultivated in vitro

2008 ◽  
Vol 22 (5) ◽  
pp. 1382-1386 ◽  
Author(s):  
Miroslav Cervinka ◽  
Zuzana Cervinkova ◽  
Emil Rudolf
Keyword(s):  
Fluorescent Microscopy ◽  
Time Lapse ◽  
Toxic Effects ◽  
Cell Populations

Activated sludge population dynamics

1994 ◽  
Vol 30 (11) ◽  
pp. 159-169 ◽  
Author(s):  
Jiri Wanner
Keyword(s):  
Population Dynamics ◽  
Activated Sludge ◽  
Organic Pollution ◽  
Paper Briefly ◽  
Microbial Composition ◽  
Selection Mechanisms ◽  
Sludge Settling

The paper briefly surveys topics covered by the IAWQ Specialist Group on Activated Sludge Population Dynamics. The activated sludge population dynamics has been formulated as a branch of water science and technology concerned with phenomena governing the relationships between activated sludge microorganisms and their functions. The characterization of organic pollution fractions in wastewaters according to their rate of biodegradation has been discussed and the role of wastewater as an inoculum stressed. The characterization of activated sludge biomass has been evaluated from two viewpoints: grouping according to metabolic abilities and identification and classification of activated sludge microorganisms. The basic selection mechanisms influencing the microbial composition of activated sludge have been described. The problems with activated sludge settling and thickening properties have been mentioned as a typical example of applied population dynamics research.

Effect of temperature on transition and transversion mutagenesis: characterization of wild type and a mutator T4 DNA polymerase mutant

1984 ◽  
Vol 26 (3) ◽  
pp. 386-389 ◽  
Author(s):  
Linda J. Reha-Krantz ◽  
Sükran Parmaksizoglu
Keyword(s):  
Dna Polymerase ◽  
Low Temperatures ◽  
Bacteriophage T4 ◽  
Effect Of Temperature ◽  
In Vitro Mutagenesis ◽  
Wild Type ◽  
Mutational Site

The effect of temperature on genetically well-defined mutational pathways was examined in the bacteriophage T4. The mutational site was a T4 rII ochre mutant which could revert to rII+ via a transversion or to the amber convertant via a transition. Temperature did not strongly affect any of the pathways examined in a wild-type background; however, increased temperature reduced the mutational activity of a mutator DNA polymerase mutant. Possible models to explain the role of temperature in mutagenesis are discussed as well as the significance of low temperatures for in vitro mutagenesis reactions.Key words: bacteriophage T4, mutator, transition, transversion, temperature effects.

scholarly journals Characterization of the Urease Operon of Brucella abortus and Assessment of Its Role in Virulence of the Bacterium

2006 ◽  
Vol 75 (2) ◽  
pp. 774-780 ◽  
Author(s):  
Félix J. Sangari ◽  
Asunción Seoane ◽  
María Cruz Rodríguez ◽  
Jesús Agüero ◽  
Juan M. García Lobo
Keyword(s):  
Brucella Abortus ◽  
Urease Activity ◽  
Strong Acid ◽  
Oral Route ◽  
Open Reading Frames ◽  
Human Brucellosis ◽  
Major Route

ABSTRACT Most members of the genus Brucella show strong urease activity. However, the role of this enzyme in the pathogenesis of Brucella infections is poorly understood. We isolated several Tn5 insertion mutants deficient in urease activity from Brucella abortus strain 2308. The mutations of most of these mutants mapped to a 5.7-kbp DNA region essential for urease activity. Sequencing of this region, designated ure1, revealed the presence of seven open reading frames corresponding to the urease structural proteins (UreA, UreB, and UreC) and the accessory proteins (UreD, UreE, UreF, and UreG). In addition to the urease genes, another gene (cobT) was identified, and inactivation of this gene affected urease activity in Brucella. Subsequent analysis of the previously described sequences of the genomes of Brucella spp. revealed the presence of a second urease cluster, ure2, in all them. The ure2 locus was apparently inactive in B. abortus 2308. Urease-deficient mutants were used to evaluate the role of urease in Brucella pathogenesis. The urease-producing strains were found to be resistant in vitro to strong acid conditions in the presence of urea, while urease-negative mutants were susceptible to acid treatment. Similarly, the urease-negative mutants were killed more efficiently than the urease-producing strains during transit through the stomach. These results suggested that urease protects brucellae during their passage through the stomach when the bacteria are acquired by the oral route, which is the major route of infection in human brucellosis.

scholarly journals Tissue-specific characterization of mitochondrial branched-chain keto acid oxidation using a multiplexed assay platform

2019 ◽  
Vol 476 (10) ◽  
pp. 1521-1537 ◽  
Author(s):  
Emma J. Goldberg ◽  
Katherine A. Buddo ◽  
Kelsey L. McLaughlin ◽  
Regina F. Fernandez ◽  
Andrea S. Pereyra ◽  
...  
Keyword(s):  
Acid Oxidation ◽  
Valuable Insight ◽  
Keto Acid ◽  
Isolated Mitochondria ◽  
Mouse Tissues ◽  
Branched Chain

Abstract Alterations to branched-chain keto acid (BCKA) oxidation have been implicated in a wide variety of human diseases, ranging from diabetes to cancer. Although global shifts in BCKA metabolism—evident by gene transcription, metabolite profiling, and in vivo flux analyses have been documented across various pathological conditions, the underlying biochemical mechanism(s) within the mitochondrion remain largely unknown. In vitro experiments using isolated mitochondria represent a powerful biochemical tool for elucidating the role of the mitochondrion in driving disease. Such analyses have routinely been utilized across disciplines to shed valuable insight into mitochondrial-linked pathologies. That said, few studies have attempted to model in vitro BCKA oxidation in isolated organelles. The impetus for the present study stemmed from the knowledge that complete oxidation of each of the three BCKAs involves a reaction dependent upon bicarbonate and ATP, both of which are not typically included in respiration experiments. Based on this, it was hypothesized that the inclusion of exogenous bicarbonate and stimulation of respiration using physiological shifts in ATP-free energy, rather than excess ADP, would allow for maximal BCKA-supported respiratory flux in isolated mitochondria. This hypothesis was confirmed in mitochondria from several mouse tissues, including heart, liver and skeletal muscle. What follows is a thorough characterization and validation of a novel biochemical tool for investigating BCKA metabolism in isolated mitochondria.

Characterization of Receptors Involved in Heparin Antibody Complex Mediated Induction of Tissue Factor Expression in Monocytes.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 224-224 ◽  
Author(s):  
Sam Glover ◽  
Nigel S. Key ◽  
Gowthami M Arepally ◽  
Nigel Mackman ◽  
Raj S. Kasthuri
Keyword(s):  
Tissue Factor ◽  
Mononuclear Cells ◽  
Conflicts Of Interest ◽  
Drug Induced ◽  
Peripheral Blood Mononuclear ◽  
Platelet Factor ◽  
Antibody Complex

Abstract Abstract 224 Introduction: Heparin-induced thrombocytopenia (HIT) is a major cause of drug-induced thrombocytopenia and occurs in 1–5% of individuals exposed to heparin. Paradoxically, 30–50% of individuals with HIT develop thrombosis. The mechanism of thrombosis in HIT is poorly understood. We recently reported that HIT antibody complexes induce tissue factor (TF) expression in monocytes and result in the release of TF-positive microparticles (MPs). The mechanism by which HIT antibody complexes induce monocyte TF has not been established. The objective of this study is to characterize the receptors involved in HIT antibody complex mediated induction of TF expression in monocytes. As HIT antibody complex mediated activation of platelets is dependent on the FcgRIIA receptor, we evaluated the role of the FcgRII receptor in the induction of monocyte TF by HIT antibody complexes. We also evaluated the role of toll like receptor-4 (TLR4) and the platelet factor 4 (PF4) chemokine receptor CXCR3 in this process. Methods: The combination of heparin, PF4 and the murine monoclonal PF4/heparin-specific antibody KKO has been shown to cause activation of platelets and monocytes, and mimic HIT in vitro. Peripheral blood mononuclear cells (PBMCs) from healthy volunteers were pre-incubated for 30 min at 37°C with an inhibitory antibody to the FcgRII receptor (IV.3); anti-CXCR2, 3, or 4 antibodies; anti-TLR4 antibody; or mouse-IgG (mIgG) control. Following pre-incubation with antibodies for 30 minutes, heparin (1U/mL), PF4 (10μg/mL), and KKO (100μg/mL) – together referred to as the HIT antibody complex – were added. Heat-aggregated mIgG and LPS were used as positive controls for the FcgRII and TLR4 receptors, respectively. Following a 6-hour incubation, PBMCs were pelleted by centrifugation and MPs were isolated from the supernatant. The procoagulant activity (PCA) of PBMCs and MPs was measured using clotting assays performed in the presence of the anti-TF antibody HTF-1 or control antibody. TF dependent PCA was calculated by reference to a standard curve generated using relipidated recombinant TF. Results: Incubation of PBMCs with heat aggregated mIgG for 6 hours resulted in significant induction of cellular TF (345 +/− 36 pg/106 cells) which was blocked by 30 min pre-incubation with the antibody IV.3 (146 +/− 17 pg/106 cells, N=3, p<.003). However, pre-incubation with IV.3 had no significant effect on TF induction (140 +/− 5 pg/106 cells) associated with the HIT antibody complex when compared to control mIgG (110 +/− 18 pg/106 cells, N=3, p<0.11). PBMCs incubated with HIT antibody complexes in the presence of a TLR-4 antibody showed less TF activity (52 +/− 4 pg/106 cells) compared to control mIgG (80 +/− 10 pg/106 cells N=3, p<0.025). A similar, partial inhibition of TF activity was also observed in PBMCs incubated with LPS in the presence of an anti-TLR4 antibody (121 +/− 3 pg/106) compared with a control antibody (89 +/− 2 pg/106, N=3, p<.0013). Experiments with a more effective inhibitor of TLR4 are in progress. PBMCs incubated with the HIT antibody complexes in the presence of an anti-CXCR3 antibody showed less TF activity (36 +/− 7 pg/mL) compared to control mIgG (118 +/− 15 pg/106 cells, N=3, p<0.004). Antibodies against CXCR2 and CXCR4 did not have any significant effect on TF induction. Measurement of MP TF activity mirrored the results described above. Using flow cytometry and an anti-CXCR3 antibody labeled with FITC, we found that 5% (± 0.5%) of monocytes expressed CXCR3 (N=3), which is consistent with the reported literature. Conclusions: These data suggest that induction of TF in monocytes by HIT antibody complexes is not mediated by the FcgRII receptor. This is contrary to the mechanism of platelet activation by these antibody complexes, which is an FcgRIIa dependent process. We found that TLR4 plays a role in HIT antibody complex mediated induction of TF in monocytes and blocking TLR4 led to a 30% decrease in TF activity. On the other hand, CXCR3 appeared to play a more significant role with blockade of CXCR3 leading to a 70% decrease in TF activity. Further characterization of the role of these receptors in HIT antibody complex mediated induction of TF expression in monocytes is required. We speculate that the extent of CXCR3 and TLR4 expression in monocytes may influence the susceptibility to developing thrombotic complications in HIT. Disclosures: No relevant conflicts of interest to declare.

scholarly journals The Chlamydia-Secreted Protease CPAF Promotes Chlamydial Survival in the Mouse Lower Genital Tract

2016 ◽  
Vol 84 (9) ◽  
pp. 2697-2702 ◽  
Author(s):  
Zhangsheng Yang ◽  
Lingli Tang ◽  
Lili Shao ◽  
Yuyang Zhang ◽  
Tianyuan Zhang ◽  
...  
Keyword(s):  
Genital Tract ◽  
Chlamydial Infection ◽  
Critical Role ◽  
Content Type ◽  
Lower Genital Tract ◽  
Successful Infection ◽  
Multiple Strains

Despite the extensivein vitrocharacterization of CPAF (chlamydialprotease/proteasome-likeactivityfactor), its role in chlamydial infection and pathogenesis remains unclear. We now report that aChlamydia trachomatisstrain deficient in expression of CPAF (L2-17) is no longer able to establish a successful infection in the mouse lower genital tract following an intravaginal inoculation. The L2-17 organisms were cleared from the mouse lower genital tract within a few days, while a CPAF-sufficientC. trachomatisstrain (L2-5) survived in the lower genital tract for more than 3 weeks. However, both the L2-17 and L2-5 organisms maintained robust infection courses that lasted up to 4 weeks when they were directly delivered into the mouse upper genital tract. The CPAF-dependent chlamydial survival in the lower genital tract was confirmed in multiple strains of mice. Thus, we have demonstrated a critical role of CPAF in promotingC. trachomatissurvival in the mouse lower genital tracts. It will be interesting to further investigate the mechanisms of the CPAF-dependent chlamydial pathogenicity.

scholarly journals Immunological changes in growing mice fed on diets containing casein or peas (Pisum sativum var. Belinda) as the source of protein

1995 ◽  
Vol 73 (1) ◽  
pp. 87-97 ◽  
Author(s):  
J.Alfredo Martínez ◽  
M. Luisa Esparza ◽  
Jesús Larralde
Keyword(s):  
Pisum Sativum ◽  
Individual Performance ◽  
Gastrointestinal Disorders ◽  
Antigenic Proteins ◽  
Poor Individual ◽  
First Time ◽  
Different Sources

The effects of two different sources of protein: peas (Pisum sativum var. Belinda) and casein on immunocompetence, nutritional utilization and growth performance have been investigated in recently weaned mice. Feeding these animals on a pea diet resulted in an impairment in growth and significant decreases in the weights of liver, muscle, kidneys and femur, while intestine weights increased. No differences in food consumption were observed, but food conversion efficiency (food intake: weight gain) was increased in pea-fed animals compared with those offered the casein diet. Packed cell volume and serum Fe and Zn levels fell significantly after legume-protein intake, and, by contrast, Cu values increased slightly. Serum albumin levels showed a statistically significant reduction in mice fed on the diet containing peas. However, y-globulins and immunoglobulin G titres were markedly increased. The characterization of spleen-cell subsets using monoclonal antibodies revealed a significantly higher percentage of T-lymphocytes in the pea group compared with casein-fed animals, while no changes were observed in the proportions of B-lymphocytes and macrophages. In vitro mitogenic responses to phytohaemagglutinin, concanavalin A and Escherichia coli lipopolysaccharide S were slightly, but not significantly, lower in the pea-fed animals. Our results describe, apparently for the first time in mice, some immunological disturbances after peak intake. These results may lead to a better understanding of the possible role of antigenic proteins in gastrointestinal disorders and the poor individual performance after legume intake.

Sign in / Sign up

Export Citation Format

Share Document