Studies on the reaction mechanism of Rhodotorula gracilis D-amino-acid oxidase. Role of the highly conserved Tyr-223 on substrate binding and catalysis.

We have studied D-amino-acid oxidase from Rhodotorula gracilis by site-directed mutagenesis for the purpose of determining the presence or absence of residues having a possible role in acid/base catalysis. Tyr-223, one of the very few conserved residues among D-amino-acid oxidases, has been mutated to phenylalanine and to serine. Both mutants are active catalysts in turnover with D-alanine, and they are reduced by D-alanine slightly faster than wild-type enzyme. The Tyr-223 --> Phe mutant is virtually identical to the wild-type enzyme, whereas the Tyr-223 --> Ser mutant exhibits 60-fold slower substrate binding and at least 800-fold slower rate of product release relative to wild-type. These data eliminate Tyr-223 as an active-site acid/base catalyst. These results underline the importance of Tyr-223 for substrate binding and exemplify the importance of steric interactions in RgDAAO catalysis

pLG72 modulates intracellular D-serine levels through its interaction with D-amino acid oxidase - Effect on schizophrenia susceptibility

Human genes coding for pLG72 and d-amino acid oxidase have recently been linked to the onset of schizophrenia. pLG72 was proposed as an activator of the human FAD-containing flavoprotein d-amino acid oxidase (hDAAO). In the brain this oxidizes d-serine, a potent activator of N-methyl-d-aspartate receptor. We have investigated the mechanistic regulation of hDAAO by pLG72. Immunohistochemical analyses revealed that hDAAO and pLG72 are both expressed in astrocytes of the human cortex, where they most likely interact, considering their partial overlapping subcellular distribution and their coimmunoprecipitation. We demonstrated that the specific in vitro interaction of the two proteins yields a complex composed of 2 hDAAO homodimers and 2 pLG72 molecules. Binding of pLG72 did not affect the kinetic properties and FAD binding ability of hDAAO; instead, a time-dependent loss of hDAAO activity in the presence of an excess of pLG72 was found. The binding affects the tertiary structure of hDAAO, altering the amount of the active form. We finally demonstrated that overexpression of hDAAO in glioblastoma cells decreases the levels of d-serine, an effect that is null when pLG72 is coexpressed. These data indicate that pLG72 acts as a negative effector of hDAAO. Therefore, a decrease in the synaptic concentration of d-serine as the result of an anomalous increase in hDAAO activity related to hypoexpression of pLG72 may represent a molecular mechanism by which hDAAO and pLG72 are involved in schizophrenia susceptibility

Light-induced High-spin State in ZnO Nanoparticles

International audienceThe effects of white-light irradiation on ∼ 20 nm diameter ZnO nanoparticles are investigated by means of electron paramagnetic resonance, near liquid-nitrogen and liquid-helium temperatures. Under dark conditions, usual core-and surface-defects are detected, respectively at g = 1.960 and g = 2.003. Under white-light illumination, the core-defect signal intensity is strongly increased, which is to be correlated to the light-induced conductivity's augmentation. Beside, a four-lines structure appears, with the same gravity center as that of the surface defects. Simulations and intensity power-dependence measurements show that this four-line-structure is very likely to arise from a localized high spin S = 2, induced by light irradiation, and subjected to a weak axial anisotropy. At 85 K, this high-spin state can last several hours after the light-irradiation removal, probably due to highly spin-forbidden recombination process. The possible excited resonant complexes at the origin of this signal are discussed. Other light-induced S = 1/2-like centers are detected as well, which depends on the nanoparticles growth conditions

The Effects of Park Based Interventions on Health: The Italian Project “Moving Parks”

Obesity and physical inactivity are global health problems responsible for the risk increment of noncommunicable diseases. To overcome these problems, interventions aimed at increasing physical activity (PA) are necessary. Green space can have a positive influence on promoting PA, so, the aim of the present study was to assess the effectiveness of the project “The moving parks project”, which provides for the administration of PA to citizens within Bologna’s parks (Italy). An ad hoc questionnaire was administered before and after three months of outdoor PA. A total of 329 adult subjects participated in the survey. At follow-up, all psychosocial parameters showed an improvement, with a reduction in the state of tension, sadness and fatigue, and an improvement in the state of energy, serenity, and vitality. The impact of the interventions carried out in the “Moving Parks project” was positive and appears to be a good strategy for improving health outcomes

Effect of a Park-Based Physical Activity Intervention on Psychological Wellbeing at the Time of COVID-19

Practicing regular physical activity in green spaces has been invocated as a promising strategy for improving wellbeing in urban settings. The aim of the study was to assess the effect of a structured park-based physical activity intervention, the “Moving Parks” project, on citizens’ wellbeing at the time of COVID-19. The intervention was carried out in six public parks in Bologna (Italy) and administered by qualified instructors (from May 2021 to September 2021). The Psychological General Well Being Index short form questionnaire was administered before and after the three months of outdoor activities. A total of 328 participants completed the questionnaire at the beginning and at the end of the project. In September 2021, all psychosocial domains of the questionnaire (anxiety, depressed mood, self-control, positive well-being, vitality energy, and vitality-tiredness) significantly improved in the female sample (p value < 0.01) and only the last two in the male sample (p value < 0.05). The “Moving Parks” project seems to be able to improve citizens’ psychological wellbeing, particularly in women

Induction of Cytotoxic Oxidative Stress by d-Alanine in Brain Tumor Cells Expressing Rhodotorula gracilis d-Amino Acid Oxidase: A Cancer Gene Therapy Strategy

Overview summary Gene-directed enzyme prodrug therapy (GDEPT) is an antineoplastic treatment strategy designed to overcome the systemic toxicity of chemotherapy by specifically expressing a foreign enzyme in malignant cells that converts a nontoxic prodrug into a cytotoxic metabolite. The relative inefficiency of current in situ gene transfer methodology suggests that enzyme/prodrug combinations that produce membrane permeable metabolites will elicit a more favorable therapeutic response. Ideally, the agent produced by the transduced cell “factories” would be cytotoxic toward both proliferating and quiescent cells. We describe a novel GDEPT approach using d-amino acid oxidase from the red yeast Rhodotorula gracilis and d-alanine as a substrate that generates hydrogen peroxide, a reactive metabolite of oxygen that has both these characteristics. We also demonstrate the ability to sensitize tumor cells to this GDEPT protocol by manipulating cellular antioxidant pathways.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63220/1/hum.1998.9.2-185.pd

Intragastric gastric band migration: erosion: an analysis of multicenter experience on 177 patients

BACKGROUND: Laparoscopic adjustable gastric banding (LAGB) has proven to be a safe and effective surgical treatment for morbid obesity. It can be a simple, fast, reversible, anatomy-preserving procedure. Despite these advantages, its long-term efficacy came into question by the occurrence of complications such as intragastric band migration. Consistent information regarding this complication is still lacking. Treatment for migration is still being debated as well. Most of the inconsistencies of these data stem from the very low number of patients reported in single-center experiences or case reports. Lack of multicenter experience is evident. The aim of this study was to perform a retrospective analysis of data on intragastric migration in a large multicenter cohort of patients who underwent LAGB. METHODS: A retrospective multicenter study on LAGB patients was performed. Data had been entered into a prospective database of the Italian Group for LapBand(®) (GILB) since January 1997. Pars flaccida and perigastric positioning were considered along with different kinds of gastric bands by the same manufacturer. Time of diagnosis, mean body mass index (BMI), presentation symptoms, and conservative and surgical therapy of intragastric migration were considered. RESULTS: From January 1997 to December 2009, a total of 6,839 patients underwent LAGB and their data were recorded [5,660 females, 1,179 males; mean age 38.5 ± 18.2 years (range 21-62 years); mean BMI = 46.7 ± 7.7 kg/m(2) (range 37.3-68.3); excess weight (EW) 61.8 ± 25.4 kg (range 36-130); %EW 91.1 ± 32.4 % (range 21-112 %)]. A total of 177 of 6,839 (2.5 %) intragastric erosions were observed. According to the postoperative time of follow-up, the diagnosis of intragastric migration was made in 74 (41.8 %), 14 (7.9 %), 38 (21.4 %), 40 (22.6 %), 6 (3.4 %), and 4 (2.2 %) banded patients at 6-12, 24, 36, 48, 60, and 72 months after banding, respectively. Most of intragastric band migration during the first 2 years occurred in bands with no or a few milliliters of filling. In patients with late erosion, the bands were adjusted several times; no band was overfilled but one was filled to the maximum or submaximum with a maximum of two adjustments. Erosions diagnosed during the first 24 months were related to the experience of the surgical staff, while late erosions were not. CONCLUSIONS: Intragastric band migration or band erosion is a rare, disturbing, and usually not life-threatening complication of gastric banding. Its pathogenesis is probably linked to different mechanisms in early (technical failure in retrogastric passage) or late (band management) presentation. It is usually asymptomatic and there is no pathognomonic presentation. A wide range of therapeutic options are available, from simple endoscopic or laparoscopic removal to early or late band replacement or other bariatric procedure. More experience and more studies are needed to lower its presentation rate and definitively clarify its pathogenesis to address the right therapeutic option

Colorectal cancer after bariatric surgery (Cric-Abs 2020): Sicob (Italian society of obesity surgery) endorsed national survey

Background: The published colorectal cancer (CRC) outcomes after bariatric surgery (BS) are conflicting, with some anecdotal studies reporting increased risks. The present nationwide survey CRIC-ABS 2020 (Colo-Rectal Cancer Incidence-After Bariatric Surgery-2020), endorsed by the Italian Society of Obesity Surgery (SICOB), aims to report its incidence in Italy after BS, comparing the two commonest laparoscopic procedures—Sleeve Gastrectomy (SG) and Roux-en-Y gastric bypass (GBP). Methods: Two online questionnaires—first having 11 questions on SG/GBP frequency with a follow-up of 5–10 years, and the second containing 15 questions on CRC incidence and management, were administered to 53 referral bariatric, high volume centers. A standardized incidence ratio (SIR—a ratio of the observed number of cases to the expected number) with 95% confidence intervals (CI) was calculated along with CRC incidence risk computation for baseline characteristics. Results: Data for 20,571 patients from 34 (63%) centers between 2010 and 2015 were collected, of which 14,431 had SG (70%) and 6140 GBP (30%). 22 patients (0.10%, mean age = 53 ± 12 years, 13 males), SG: 12 and GBP: 10, developed CRC after 4.3 ± 2.3 years. Overall incidence was higher among males for both groups (SG: 0.15% vs 0.05%; GBP: 0.35% vs 0.09%) and the GBP cohort having slightly older patients. The right colon was most affected (n = 13) and SIR categorized/sex had fewer values < 1, except for GBP males (SIR = 1.07). Conclusion: Low CRC incidence after BS at 10 years (0.10%), and no difference between procedures was seen, suggesting that BS does not trigger the neoplasm development