Lactonase Activity Research Articles

The effect of divalent metal chelators and cadmium on serum phosphotriesterase, lactonase and arylesterase activities of paraoxonase 1

Paraoxonase 1 (PON1) is calcium dependent enzyme involved in many functions in human body. PON1 is synthesized in the liver and secreted to the bloodstream where bounds high-density lipoproteins (HDL). Association of PON1 with HDL increases the enzyme stability and biological activities. PON1 have three different activities: phosphotriesterase, lactonase and arylesterase. Until now there is now commercial available kits to determine these three PON1 activities. Also there is no date about stability of PON1 in serum after storage condition. We have elaborated the optimal conditions for determination of PON1 activities in serum using manual procedure as well as the best storage temperature of human serum for determination of PON1 activities. We have also confirmed that PON1 in serum is associated with HDL. Additionally we have investigated the effect of D-penicillamine, ethylenediaminetetraacetic acid and cadmium chloride on PON1 activities in human serum. D-penicillamine and ethylenediaminetetraacetic acid in therapeutic doses as well as cadmium chloride in toxic doses decrease PON1 activities in human serum when compared to non-treated serum. D-penicillamine as metal chelator inhibits much stronger PON1 activities than ethylenediaminetetraacetic acid.

PON2 Exemplifies a Unique Dependency of B Cell Lineage ALL Cells on Detoxifying Lactonases

Background and significance: Paraoxonase 2 (PON2) is a member of mammalian detoxifying enzymes that are located to the mitochondrial membrane, hydrolyze lactone metabolites and interact with coenzyme Q10 to diminish oxidative stress. While PON2 is highly expressed in the CNS and multiple fetal tissues, expression levels in normal hematopoietic cells are low. We began to study the function of PON2 in B cell lineage ALL, because microarray analyses suggested high mRNA levels of PON2 in B cell lineage ALL cells. In addition, PON2 is used as a diagnostic marker on a 15 gene diagnostic LDA panel (e.g. in AALL1131; NCT02883049) that is used for the identification of Ph-like ALL, a subgroup with particularly poor outcome and specific treatment requirements.Results: Analyzing data from pediatric and adult clinical trials, we found that greater than median PON2 mRNA levels at the time of diagnosis predicted poor clinical outcomes for both children (COG P9906; n=207; P=1.09e-05) and adults (ECOG; n=215; P=0.003) with B-lineage ALL. Studying expression levels of PON2 by quantitative RT-PCR and Western blot in normal bone marrow B cell precursors from healthy donors and patient-derived pre-B ALL cells including Ph+ and Ph -like ALL, we found 3-10-fold increased mRNA and protein levels of PON2 throughout multiple pre-B ALL samples. To elucidate potential functions of PON2 in normal B cells and B-lineage ALL, we studied normal B cell development and ALL-models in Pon2-/- mice. While B cell development was unperturbed in Pon2 -deficient mice, deletion of Pon2 had profound effects on both BCR-ABL1- and N RASG12D-driven leukemogenesis. Compared to wildtype, Pon2-/- pre-B ALL cells failed to form colonies in semisolid agar. Pon2-/-ALL cells were arrested in G0/G1 phase and expressed 2-5-fold increased levels of Arf and p21, compared to Pon2+/+ ALL cells. Strikingly, >50% of Pon2-/-ALL cells spontaneously underwent cellular senescence, as shown by b-galactosidase staining in conjunction with increased Arf expression levels. These in vitro findings suggest an important role of PON2 in B-lymphoid leukemogenesis, which was confirmed in transplant experiments based on BCR-ABL1 and N RASG12D ALL models. While Pon2 -deficiency substantially prolonged survival of recipient mice of BCR-ABL1 ALL cells (P=0.0001), mice transplanted with Pon2 -deficient N RASG12D ALL cells survived for indefinite periods of time.Targeting PON2 expression in relapse ALL: Given that PON2 is expressed at very high levels in relapse ALL samples, we tested the concept of targeting PON2 lactonase activity in a prodrug-approach. While PON2 activity typically results in detoxification of lactone-metabolites, lactone-hydrolysis of the N-(3-oxododecanoyl)-homoserine lactone (3OC12) prodrug results in cytotoxic byproducts (Guoping et al., 2016). We therefore tested the therapeutic potential of 3OC12. For genetic validation, we treated wildtype and Pon2-/- ALL cells with 3OC12 and found strong cytotoxic effects in wildtype but not Pon2-/- ALL cells. Likewise, inducible overexpression of Pon2 in patient-derived pre-B ALL cells exacerbated toxicity of 3OC12 compared to empty vector controls. Likewise, CRISPR-Cas9 mediated ablation of PON2 in human ALL PDX reversed sensitivity of the pre-B ALL cells to 3OC12.Conclusion: Here we describe the previously unknown function of the detoxifying PON2 lactonase as an essential prerequisite for pre-B cell transformation and leukemogenesis. PON2 expression is specific for leukemia cells, an outcome predictor for patients with pre-B ALL and a biomarker of Ph-like ALL. While PON2 protects ALL cells and enables malignant growth, we demonstrate that its lactonase-activity can be leveraged for pharmacological targeting as exemplified by the lactone-prodrug 3OC12. DisclosuresNo relevant conflicts of interest to declare.

Effect of certain non-steroidal anti-inflammatory drugs on the paraoxonase 2 (PON2) in human monocytic cell line U937

The paraoxonase gene family in humans consists of three members as PON1, PON2 and PON3. PON2 can be expressed in several tissues; however, it is not released from the cells in those tissues. PON2 is also expressed in macrophages. Firstly, the commonly used NSAIDs diclofenac sodium and tenoxicam were applied on U937 cell line, the in vitro human monocyte cell line. Than PON2 specific Lactonase activity and paraoxonase family specific arylesterase were determined. Use of Diclofenac sodium in 0.845 mM dose during 6–12 h of incubation and Tenoxicam in 0.74 mM dose during 6 h of incubation resulted in a significant decline in the lactonase activity. Diclofenac sodium didn’t make any change in the arylesterase activity. On the other hand, tenoxicam decreased arylesterase activity during the use of 12 h, in 0.74 mM and 1.48 mM dose.

Paraoxonase, arylesterase and lactonase activities of paraoxonase-1 (PON1) in obese and severely obese women

Obesity is independently associated with disturbances in lipid and lipoprotein metabolism, oxidative stress, and is a well-established independent risk factor for cardiovascular diseases (CVD). Human paraoxonase 1 (PON1) is a pleotropic high-density lipoprotein (HDL)-associated enzyme with antioxidant and anti-inflammatory proprieties that have been suggested to contribute to the athero-protective function of the lipoprotein. The aim of this study was to investigate whether obesity is associated with PON1 activity and whether this association is influenced by oxidative stress, inflammation and HDL cholesterol (HDL-C) concentration. The promiscuous activities, arylesterase and paraoxonase, and the putative physiological activity, lactonase, of PON1 were assessed in the serum of 214 obese and severely obese, 101 overweight and 129 normal-weight women. Levels of high-sensitivity C-reactive protein (hs-CRP), hydroperoxides (by-products of lipid oxidative damage) and lipid profiles were also evaluated. Arylesterase activity was the only activity that significantly differed across the groups (ANOVA, p < .01), with the greatest decrease observed in individuals with body mass index (BMI) > 40 kg/m2 compared to controls (p < .001). This activity was also inversely, although weakly (r = −0.160, p < .001) correlated with the BMI, and the association was independent of age and levels of oxidative stress and inflammation, but not of HDL-C concentration. In conclusion, our results suggest that the apparent obesity-associated decrement of PON1 activity might simply reflect the decrease in concentration of its plasmatic carrier.

Catalytic Characteristics of New Antibacterials Based on Hexahistidine-Containing Organophosphorus Hydrolase

Catalytic characteristics of hexahistidine-containing organophosphorus hydrolase (His6-OPH) and its enzyme-polyelectrolyte complexes with poly-l-glutamic acid or poly-l-aspartic acid (His6-OPH/PLD50), hydrolyzing organophosphorous compounds, and N-acyl homoserine lactones were studied in the presence of various antibiotics (ampicillin, gentamicin, kanamycin, and rifampicin). The antibiotics at concentrations below 1 g·L−1 had a negligible inhibiting effect on the His6-OPH activity. Mixed inhibition of His6-OPH was established for higher antibiotic concentrations, and rifampicin was the most potent inhibitor. Stabilization of the His6-OPH activity was observed in the presence of antibiotics at a concentration of 0.2 g·L−1 during exposure at 25–41 °C. Molecular docking of antibiotics to the surface of His6-OPH dimer revealed the antibiotics binding both to the area near active centers of the enzyme subunits and to the region of contact between subunits of the dimer. Such interactions between antibiotics and His6-OPH were verified with Fourier-transform infrared (FTIR) spectroscopy. Considering all the results of the study, the combination of His6-OPH/PLD50 with β-lactam antibiotic ampicillin was established as the optimal one in terms of exhibition and persistence of maximal lactonase activity of the enzyme.

His6-OPH and Its Stabilized Forms Combating Quorum Sensing Molecules of Gram-Negative Bacteria in Combination with Antibiotics

Background: In most species of gram-negative pathogenic and conditionally pathogenic bacteria, quorum sensing-dependent systems have been discovered, in which various N-acyl-L-homoserine lactones function as signaling molecules inducing the development of resistance towards the effects of antibiotics. Objectives: The purpose of this study was to investigate the possibility of stabilizing lactonase activity of His6-OPH by forming enzyme polyelectrolyte non-covalent complexes (EPNCs) containing both this enzyme and polyanionic polymer. It also targeted at studying the efficacy of these EPNCs in combination with a variety of antibiotics (ampicillin, gentamicin, kanamycin, and rifampicin) against gram-negative bacteria. Cheap non-toxic biodegradable polyamino acids (poly-L-glutamic acid and poly-L-aspartic acid) were selected as polyanionic polymers to produce EPNCs. Methods: Recombinant Escherichia coli strain SG13009 [pREP4], transformed by plasmid encoding His6-OPH, was used for His6-OPH production. The His6-OPH lactonase activity was determined according to known methods, using a pH-sensitive indicator (cresol red) and a colorimetric method. The minimum inhibitory concentration (MIC) of antibiotics was determined with the suspension of bacteria cells, with antibiotic added in a concentration range from 0 to 500 mg/L at 37°C during 16 hours. Results: All the tested enzyme preparations were equally efficient in catalyzing the hydrolysis of N-acyl-homoserine lactones of various structures containing and lacking a 3-oxo group in the acyl radical. It has been established that the presence of enzyme preparations facilitates the reduction of MIC of antibiotics (ampicillin, gentamicin sulfate, kanamycin sulfate, and rifampicin) on the growth of highly concentrated (106 cells/mL) cell populations of Pseudomonas aeruginosa B-6643 and Escherichia coli B-6645. Polyelectrolyte complexes of this enzyme have an increased efficiency at a lower pH (6.5) of the medium in comparison to its highly purified form. It is possible to reduce the minimum inhibitory concentration of antibiotics by 10% to 850% in combined use of antibiotics and His6-OPH enzyme preparations. Conclusions: The discussed approaches for the use of original biological products based on His6-OPH opens up opportunities for creating new ways of effectively controlling bacterial diseases in animals.

Karakterisasi Enzim Pendegradasi AHL dari Bacillus cereus INT1c dan Bacillus sp. NTT3a

Some of Gram-negative bacteria perform a phenomenon called quorum sensing (QS) to activate certain phenotypes such as pathogenicity. The bacterial cells performing QS produce N-acyl homoserine lactone (AHL) as signal molecules to communicate within a population. These molecules can be degraded by the enzyme, i.e. AHL lactonase. This study aimed to characterize the activity of AHL lactonase from Bacillus cereus INT1c and Bacillus sp. NTT3a in different pH and temperature levels. Both strains produce AHL-lactonase that could be found in intracellular and extracellular extracts. The dialysis process of extracellular AHL-lactonase of INT1c significantly increased the specific activity from 5.91 to 29.96, different from an extracellular enzyme of NTT3a that slightly increased from 4.08 to 5.39. Generally dialyzedAHL-lactonase of both B. cereus INT1c and Bacillus sp. NTT3a had activity in wide pH range with better activity in acidic pH and were not stable in high temperature with the highest activity at 30-40 oC.

Karakterisasi Enzim Pendegradasi AHL dari Bacillus cereus INT1c dan Bacillus sp. NTT3a

Some of Gram-negative bacteria perform a phenomenon called quorum sensing (QS) to activate certain phenotypes such as pathogenicity. The bacterial cells performing QS produce N-acyl homoserine lactone (AHL) as signal molecules to communicate within a population. These molecules can be degraded by the enzyme, i.e. AHL lactonase. This study aimed to characterize the activity of AHL lactonase from Bacillus cereus INT1c and Bacillus sp. NTT3a in different pH and temperature levels. Both strains produce AHL-lactonase that could be found in intracellular and extracellular extracts. The dialysis process of extracellular AHL-lactonase of INT1c significantly increased the specific activity from 5.91 to 29.96, different from an extracellular enzyme of NTT3a that slightly increased from 4.08 to 5.39. Generally dialyzedAHL-lactonase of both B. cereus INT1c and Bacillus sp. NTT3a had activity in wide pH range with better activity in acidic pH and were not stable in high temperature with the highest activity at 30-40 oC.

Lactonase activity of HDL is increased in morbidly obese subjects and is associated to atherogenic index of plasma

Aim: The relationship between HDL and cardiovascular risk is complex because the cardiovascular risk assessment does not depend only of HDL levels. One of the properties of HDL is the antioxidant capacity, due to paraoxonase, lactonase and arylesterase activities of the paraoxonase enzyme present in HDL. We aim to analyze the antioxidant capacity of HDL in subjects with morbid obesity, and its evolution after Roux-en-Y gastric bypass (RYGB).

Alteration of paraoxonase, arylesterase and lactonase activities in people around fluoride endemic area of Tamil Nadu, India

BackgroundToxicity due to excess fluoride concentration in drinking water is of great concern in people who rely only on the ground water as their water source in many region of the world. MethodsWe collected samples and examined the toxicity of fluoride in a population residing at Salem, Dharmapuri and Krishnagiri districts of Tamil Nadu, India and measured HDL bound enzyme (PON1), erythrocyte membrane bound enzymes (acetylcholinesterase, AChE) and adenosine 5′ triphosphatase (ATPases), plasma enzyme (butyrylcholinesterase, BChE) and rate limiting enzyme in heme biosynthesis (delta aminolevulinic acid dehydratase, δ-ALAD) activities. ResultsIn fluorosis patients, formation of lipid peroxidation product was more in erythrocytes than in plasma. The observation further revealed that there was 50% reduction in the activity of HDL bound anti atherogenic enzyme-paraoxonase (PON1). The activities of membrane bound and signaling enzymes (acetylcholinesterase - AChE and adenosine 5′ triphosphatase - ATPase) of erythrocyte were also diminished. These results suggested that there was defectiveness in the signaling and energy metabolism in fluorosis patients. Altered isoenzyme pattern of lactate dehydrogenase (LDH) in fluorosis samples was observed. Furthermore, the result suggested that both the heart (LDH 1) and liver (LDH 5) were most affected by fluoride toxicity. The study also provided reference values for tests which are used to predict the severity of fluoride toxicity. ConclusionThe toxic effect of fluoride was due to the collective effects on vital protective system rather than single factor.

The effect of passive and active exposure to tobacco smoke on lipid profile parameters and the activity of certain membrane enzymes in the blood of women in the first trimester of pregnancy

The effect of tobacco smoke on lipid peroxidation, the lipid profile and membrane-bound enzymatic activity in the first trimester of pregnancy was investigated.In the plasma of women with active exposure to tobacco smoke, we have found increased lipid peroxidation and higher total concentrations of cholesterol, triglycerides and low-density lipoproteins in the blood, as well as a decreased concentration of high-density lipoproteins. A higher concentration of low-density lipoproteins and a lower concentration of high-density lipoproteins were also found in the plasma of passive smokers. In contrast, women who smoked before pregnancy had only a higher low-density lipoprotein concentration. In the group of active and passive smoking women, lower arylesterase and phosphotriesterase activities of paraoxonase were observed, while the lactonase activity of paraoxonase decreased only in the group of active smoking women. In women with active exposure to tobacco smoke, a higher activity level of alanine aminopeptidase and γ-glutamyltransferase in the plasma was found.It is important to monitor the lipid profile during pregnancy, especially when exposure to tobacco smoke occurs.

HqiA, a novel quorum-quenching enzyme which expands the AHL lactonase family

The screening of a metagenomic library of 250,000 clones generated from a hypersaline soil (Spain) allowed us to identify a single positive clone which confers the ability to degrade N-acyl homoserine lactones (AHLs). The sequencing of the fosmid revealed a 42,318 bp environmental insert characterized by 46 ORFs. The subcloning of these ORFs demonstrated that a single gene (hqiA) allowed AHL degradation. Enzymatic analysis using purified HqiA and HPLC/MS revealed that this protein has lactonase activity on a broad range of AHLs. The introduction of hqiA in the plant pathogen Pectobacterium carotovorum efficiently interfered with both the synthesis of AHLs and quorum-sensing regulated functions, such as swarming motility and the production of maceration enzymes. Bioinformatic analyses highlighted that HqiA showed no sequence homology with the known prototypic AHL lactonases or acylases, thus expanding the AHL-degrading enzymes with a new family related to the cysteine hydrolase (CHase) group. The complete sequence analysis of the fosmid showed that 31 ORFs out of the 46 identified were related to Deltaproteobacteria, whilst many intercalated ORFs presented high homology with other taxa. In this sense, hqiA appeared to be assigned to the Hyphomonas genus (Alphaproteobacteria), suggesting that horizontal gene transfer had occurred.

Influence of oral contraceptives on lipid profile and paraoxonase and commonly hepatic enzymes activities.

The aim of the study was to verify the influence of oral contraceptives (OCs) on lipid profile and the arylesterase, lactonase and phosphotriesterase activities of paraoxonase 1 (PON1). Also commonly hepatic enzymes: aspartate aminotransferase (AST), alanine aminotransferase (ALT) and γ-glutamyltranspherase (GGT) were measured. Lipid profile and hepatic enzymes were determined using commercial available reagents. Paraoxonase activities were estimated using earlier published procedures. Blood samples were collected from 120 women of similar age (22.6±1.0years) with similar BMI (20.71±2.20kg/m2 ). Participations were divided into two groups: 74 females do not take (group A) and 46 women taking OCs (group B). Higher triglycerides and lower low-density lipoproteins levels were observed in group B than in group A) (56.9±19.7mg/dL. Castelli risk index I was significantly higher in group B when compared to group A (P<.0001), whereas we did not observe any statistically significant differences in Castelli risk index II value between studied groups. In group B, increase in ALT, AST and GGT activities were found, while the de Ritis ratio was lower in group B than in group A. In group B, lower phosphotriesterase activity and higher arylesterase and lactonase activities were found when compared to group A. Higher ALT, AST and GGT activities in serum as well as changes in lipid profile and PON activities can indicate that OCs usage can cause disorder in these parameters in the serum of women taking OCs.

Towards Understanding the Catalytic Mechanism of Human Paraoxonase 1: Experimental and In Silico Mutagenesis Studies

Human paraoxonase 1 (h-PON1) is a ~45-kDa serum enzyme that can hydrolyze a variety of substrates, including organophosphate (OP) compounds. It is a potential candidate for the development of antidote against OP poisoning in humans. However, insufficient OP-hydrolyzing activity of native enzyme affirms the urgent need to develop improved variant(s) having enhanced OP-hydrolyzing activity. The crystal structure of h-PON1 remains unsolved, and the molecular details of how the enzyme catalyses hydrolysis of different types of substrates are also not clear. Understanding the molecular details of the catalytic mechanism of h-PON1 is essential to engineer better variant(s) of enzyme. In this study, we have used a random mutagenesis approach to increase the OP-hydrolyzing activity of recombinant h-PON1. The mutants not only showed a 10-340-fold increased OP-hydrolyzing activity against different OP substrates but also exhibited differential lactonase and arylesterase activities. In order to investigate the mechanistic details of the effect of observed mutations on the hydrolytic activities of enzyme, molecular docking studies were performed with selected mutants. The results suggested that the observed mutations permit differential binding of substrate/inhibitor into the enzyme's active site. This may explain differential hydrolytic activities of the enzyme towards different substrates.

Active Site Hydrophobicity and the Convergent Evolution of Paraoxonase Activity in Structurally Divergent Enzymes: The Case of Serum Paraoxonase 1.

Serum paraoxonase 1 (PON1) is a native lactonase capable of promiscuously hydrolyzing a broad range of substrates, including organophosphates, esters, and carbonates. Structurally, PON1 is a six-bladed β-propeller with a flexible loop (residues 70–81) covering the active site. This loop contains a functionally critical Tyr at position 71. We have performed detailed experimental and computational analyses of the role of selected Y71 variants in the active site stability and catalytic activity in order to probe the role of Y71 in PON1’s lactonase and organophosphatase activities. We demonstrate that the impact of Y71 substitutions on PON1’s lactonase activity is minimal, whereas the kcat for the paraoxonase activity is negatively perturbed by up to 100-fold, suggesting greater mutational robustness of the native activity. Additionally, while these substitutions modulate PON1’s active site shape, volume, and loop flexibility, their largest effect is in altering the solvent accessibility of the active site by expanding the active site volume, allowing additional water molecules to enter. This effect is markedly more pronounced in the organophosphatase activity than the lactonase activity. Finally, a detailed comparison of PON1 to other organophosphatases demonstrates that either a similar “gating loop” or a highly buried solvent-excluding active site is a common feature of these enzymes. We therefore posit that modulating the active site hydrophobicity is a key element in facilitating the evolution of organophosphatase activity. This provides a concrete feature that can be utilized in the rational design of next-generation organophosphate hydrolases that are capable of selecting a specific reaction from a pool of viable substrates.

Leptin and adiponectin as new markers of undernutrition in cancer

ObjectivesTo evaluate leptin and adiponectin as markers of undernutrition in cancer patients, and compare their performances with those of other biomarkers. Design and methodsThis was a prospective and observational study of 132 patients with various types of cancer. Following the recommended professional criteria, we diagnosed undernutrition at the time of blood sampling for the biological analysis of leptin, adiponectin, paraoxonase (hydrolysis rate of three substrates: paraoxon (PON), phenylacetate (ARE) and thiolactone (LAC)), and the calculation of the Prognostic Inflammatory and Nutritional Index (PINI). Patients were monitored for one year to establish the mortality rate of the group. Relationships between biological variables and undernutrition were evaluated using univariate and multivariate logistic regression models. The Kaplan Meier method was used to analyse survival curves. Hazard ratios for death were calculated according to the quartiles of each biological variable. ResultsIn the case of undernutrition, a decrease was observed in levels of leptin and in the lactonase activity (LAC) of paraoxonase, while adiponectin levels increased. Besides PINI, leptin was the only parameter that was independently related to undernutrition. While no relation was found between survival and leptin or adiponectin levels, evidence was found that PINI, LAC and ARE were associated with survival, even in multivariate analysis. ConclusionsLeptin and PINI are good markers of installed undernutrition, and PINI and ARE or LAC are reliable markers of the risk of death in patients suffering from cancer.

Lactonase Activity and Lipoprotein-Phospholipase A2 as Possible Novel Serum Biomarkers for the Differential Diagnosis of Autism Spectrum Disorders and Rett Syndrome: Results from a Pilot Study.

Rett syndrome (RTT) and autism spectrum disorders (ASDs) are not merely expression of brain dysfunction but also reflect the perturbation of physiological/metabolic homeostasis. Accordingly, both disorders appear to be associated with increased vulnerability to toxicants produced by redox imbalance, inflammation, and pollution, and impairment of systemic-detoxifying agents could play a role in the exacerbation of these detrimental processes. To check this hypothesis, the activities of two mechanistically related blood-based enzymes, paraoxonase-1 (arylesterase, paraoxonase, and lactonase), and lipoprotein-associated phospholipase A2 (Lp-PLA2) were measured in the serum of 79 ASD and 95 RTT patients, and 77 controls. Lactonase and Lp-PLA2 showed a similar trend characterized by significantly lower levels of both activities in ASD compared to controls and RTT (p < 0.001 for all pairwise comparisons). Noteworthy, receiving operator curve (ROC) analysis revealed that lactonase and, mostly, Lp-PLA2 were able to discriminate between ASD and controls (lactonase: area under curve, AUC = 0.660; Lp-PLA2, AUC = 0.780), and, considering only females, between ASD and RTT (lactonase, AUC = 0.714; Lp-PLA2, AUC = 0.881). These results suggest that lactonase and, especially, Lp-PLA2 activities might represent novel candidate biomarkers for ASD.

An intensive lifestyle intervention reduces circulating oxidised low-density lipoprotein and increases human paraoxonase activity in obese subjects

Obesity has a great impact on cardiovascular morbidity and mortality, the treatment of this pathological state is important given the significant health consequences. Lifestyle and behaviour changes play a significant role in weight management. The purpose of this study was to investigate the impact of an intensive multidisciplinary lifestyle intervention on well-known atherogenic factors in a group of overweight and obese subjects. A total of 44 people with overweight/obesity underwent a lifestyle intervention based on nutritional education, psychological support and a 3-month exercise training program with a frequency of twice a week. Several anthropometric and biochemical parameters were measured before and after the lifestyle intervention. Lifestyle intervention led to a significant reduction in metabolic profile including body mass index (BMI), waist circumference, systolic and diastolic blood pressure, plasma glucose, and plasma triglycerides. These reductions were also accompanied by a significant increase in maximal oxygen consumption and muscle strength. Furthermore, paraoxonase and lactonase activities and the concentration of Apoliproteins A1 (APO A1) were significantly increased and the serum levels of oxLDL reduced without any changes in the circulating levels of LDL and HDL. In conclusion, our study suggests that an intensive lifestyle intervention in obese subjects promotes a series of beneficial antiatherogenic changes which included increased enzyme activites of paraoxonase and lactonase, concentration of Apoliproteins A1 and decreased circulating levels of oxLDL.

Harnessing hyperthermostable lactonase from Sulfolobus solfataricus for biotechnological applications.

Extremozymes have gained considerable interest as they could meet industrial requirements. Among these, SsoPox is a hyperthermostable enzyme isolated from the archaeon Sulfolobus solfataricus. This enzyme is a lactonase catalyzing the hydrolysis of acyl-homoserine lactones; these molecules are involved in Gram-negative bacterial communication referred to as quorum sensing. SsoPox exhibits promiscuous phosphotriesterase activity for the degradation of organophosphorous chemicals including insecticides and chemical warfare agents. Owing to its bi-functional catalytic abilities as well as its intrinsic stability, SsoPox is appealing for many applications, having potential uses in the agriculture, defense, food and health industries. Here we investigate the biotechnological properties of the mutant SsoPox-W263I, a variant with increased lactonase and phosphotriesterase activities. We tested enzyme resistance against diverse process-like and operating conditions such as heat resistance, contact with organic solvents, sterilization, storage and immobilization. Bacterial secreted materials from both Gram-negative and positive bacteria were harmless on SsoPox-W263I activity and could reactivate heat-inactivated enzyme. SsoPox showed resistance to harsh conditions demonstrating that it is an extremely attractive enzyme for many applications. Finally, the potential of SsoPox-W263I to be active at subzero temperature is highlighted and discussed in regards to the common idea that hyperthermophile enzymes are nearly inactive at low temperatures.

Circulating Fibroblast Growth Factor-23 Level and Paraoxonase-1 Lactonase Activity in Chronic Hemodialysis Patients: Their Impact on the Incidence of Native AV Fistula Thrombosis.

Thrombosis of native arteriovenous (AV) fistula is an important cause of complications in hemodialysis (HD) patients. The purpose of this study was to investigate the usefulness of measuring circulating fibroblast growth factor-23 (FGF-23) level and paraoxonase-1 (PON1) lactonase activity as potential predictors of native AV fistula thrombosis in chronic HD patients. This study included 83 HD patients (48 with thrombosed and 35 with non-thrombosed native AV fistulas) and 38 healthy volunteers. Serum FGF-23 level was measured using the ELISA technique, while serum PON1 lactonase activity was measured spectrophotometrically using gamma-thiobutyrolactone as a substrate. FGF-23 was significantly increased while PON1 lactonase was markedly decreased in both thrombosed and non-thrombosed HD patients compared with controls (P < 0.001). FGF-23 was elevated whereas PON1 lactonase was decreased in HD patients with thrombosed native AV fistulas compared with HD patients with non-thrombosed native AV fistulas (P = 0.001 and 0.002, respectively). A significant negative correlation was found between FGF-23 and PON1 lactonase in HD patients with thrombosed native AV fistulas (r = -0.342, P = 0.017). This study shows a potential value of FGF-23 and PON1 lactonase as predictors of native AV fistula thrombosis in HD patients.