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1.
Sci Total Environ ; 948: 174847, 2024 Oct 20.
Article in English | MEDLINE | ID: mdl-39025142

ABSTRACT

Citizen science has been particularly effective in gathering reliable, timely, large-scale data on the presence and distributions of animal species, including mosquito vectors of human and zoonotic pathogens. This involves the participation of citizen scientists in research projects, with success strongly dependent on the capacity to disseminate project information and engage citizen scientists to contribute their time. Mosquito Alert is a citizen science that aids in the system surveillances of vector mosquitoes. It involves citizen scientists providing expert-validated photos of targeted mosquitoes, along with records of bites and breeding sites. Since 2020 the system has been disseminated throughout Europe. This article uses models to analyze the effect of promotion activities carried out by the Mosquito Alert ITALIA team from October 2020 to December 2022 on the number of citizen scientists recruited and engaged in the project, and their performance in mosquito identification. Results show a high level of citizen scientist recruitment (N > 18.000; 37 % of overall European participants). This was achieved mostly through articles generated by ad hoc press releases detailing the app's goals and functioning. Press releases were more effective when carried out at the beginning and end of the mosquito season and when mosquito's public health significance was emphasized. Despite the high number of records received (N > 20.000), only 30 % of registered participants sent records, and the probability of a participant sending a record dropped off quickly over time after first registering. Among participants who contributed, ∼50 % sent 1 record, ∼30 % ≥3 and 4 % >10 records. Participants showed good capacity to identify mosquitoes and improve identification skills with app usage. The results will be valuable for anyone interested in evaluating citizen science, as participation and engagement are seldom quantitatively assessed. Our results are also useful for designing dissemination and education strategies in citizen science projects associated with arthropod vector monitoring.


Subject(s)
Citizen Science , Mosquito Vectors , Zoonoses , Italy , Animals , Humans , Arthropod Vectors , Culicidae , Mosquito Control/methods
2.
Res Sq ; 2024 Mar 18.
Article in English | MEDLINE | ID: mdl-38562903

ABSTRACT

The two main Afrotropical malaria vectors - Anopheles coluzzii and An. gambiae - are genetically distinct and reproductively isolated across West Africa. However, populations at the western extreme of their range are assigned as "intermediate" between the two species by whole genome sequence (WGS) data, and as hybrid forms by conventional molecular diagnostics. By exploiting WGS data from 1,190 specimens collected across west Africa via the Anopheles gambiae 1000 Genomes network, we identify a novel putative taxon in the far-west (provisionally named Bissau molecular form), which did not arise by admixture but rather originated at the same time as the split between An. coluzzii and An. gambiae. Intriguingly, these populations lack insecticide resistance mechanisms commonly observed in the two main species. These findings lead to a change of perspective on malaria vector species in the far-west region with potential for epidemiological implications, and a new challenge for genetic-based mosquito control approaches.

3.
Monaldi Arch Chest Dis ; 79(1): 8-11, 2013 Mar.
Article in English | MEDLINE | ID: mdl-23741940

ABSTRACT

BACKGROUND AND AIM: The hazardous health effects of smoking and second-hand smoke are well known and have been confirmed in several studies. We wondered whether a school based programme involving media models such as those represented by famous soccer players and TV characters, was effective in prevention of smoking habit in secondary school adolescents. METHODS: Since October 2006 to May 2007 an anonymous survey was submitted to 1382 secondary schools pupils. After completing the questionnaire all students of 42 out of 70 classes selected by the school principals underwent a prevention programme consisting of 1 hour lecture on smoke healthy hazard with educational material (slides, video, leaflets). Furthermore each pupil was given card games with significant pictures. Since October 2007 to May 2008 and Since October 2008 to May 2009 pupils underwent a 1 hour interactive lesson on smoke related health hazards respectively. On December 2007 pupils in study attended a theatre event with show business characters acting to smoke dissuasion. No intervention was performed on the 568 pupils of the other classes along all the same 2 school- year period (controls). RESULTS: Among other results at the end of the 2-year program 4% pupils of study group and 14% of controls reported smoking habit (p = 0.001) whereas 7% and 27% (p = 0.001) of study and control pupils respectively ignored smoking induced dependence. CONCLUSION: A school based programme involving media models such as those represented by famous soccer players, TV characters, was effective in prevention of smoking habit in secondary school adolescents.


Subject(s)
Health Education , Schools , Smoking Prevention , Child , Female , Humans , Male , Surveys and Questionnaires
4.
Sci Rep ; 11(1): 6256, 2021 03 18.
Article in English | MEDLINE | ID: mdl-33737616

ABSTRACT

Evidences of an association between air pollution and Covid-19 infections are mixed and inconclusive. We conducted an ecological analysis at regional scale of long-term exposure to air-borne particle matter and spread of Covid-19 cases during the first wave of epidemics. Global air pollution and climate data were calculated from satellite earth observation data assimilated into numerical models at 10 km resolution. Main outcome was defined as the cumulative number of cases of Covid-19 in the 14 days following the date when > 10 cumulative cases were reported. Negative binomial mixed effect models were applied to estimate the associations between the outcome and long-term exposure to air pollution at the regional level (PM10, PM2.5), after adjusting for relevant regional and country level covariates and spatial correlation. In total we collected 237,749 Covid-19 cases from 730 regions, 63 countries and 5 continents at May 30, 2020. A 10 µg/m3 increase of pollution level was associated with 8.1% (95% CI 5.4%, 10.5%) and 11.5% (95% CI 7.8%, 14.9%) increases in the number of cases in a 14 days window, for PM2.5 and PM10 respectively. We found an association between Covid-19 cases and air pollution suggestive of a possible causal link among particulate matter levels and incidence of COVID-19.


Subject(s)
Air Pollution/adverse effects , COVID-19/epidemiology , Particulate Matter/adverse effects , COVID-19/etiology , Humans , Incidence
5.
Pulmonology ; 2021 Apr 17.
Article in English | MEDLINE | ID: mdl-33879426

ABSTRACT

The design of e-cigarettes (e-cigs) is constantly evolving and the latest models can aerosolize using high-power sub-ohm resistance and hence may produce specific particle concentrations. The aim of this study was to evaluate the aerosol characteristics generated by two different types of electronic cigarette in real-world conditions, such as a sitting room or a small office, in number of particles (particles/cm3). We compared the real time and time-integrated measurements of the aerosol generated by the e-cigarette types Just Fog and JUUL. Real time (10s average) number of particles (particles/cm3) in 8 different aerodynamic sizes was measured using an optical particle counter (OPC) model Profiler 212-2. Tests were conducted with and without a Heating, Ventilating Air Conditioning System (HVACS) in operation, in order to evaluate the efficiency of air filtration. During the vaping sessions the OPC recorded quite significant increases in number of particles/cm3. The JUUL e-cig produced significantly lower emissions than Just Fog with and without the HVACS in operation. The study demonstrates the rapid volatility or change from liquid or semi-liquid to gaseous status of the e-cig aerosols, with half-life in the order of a few seconds (min. 4.6, max 23.9), even without the HVACS in operation. The e-cig aerosol generated by the JUUL proved significantly lower than that generated by the Just Fog, but this reduction may not be sufficient to eliminate or consistently reduce the health risk for vulnerable non e-cig users exposed to it.

6.
Ann Oncol ; 21(7): 1404-1409, 2010 Jul.
Article in English | MEDLINE | ID: mdl-20089563

ABSTRACT

A cancer patient who smokes is a very fragile person and we identify in scientific literature three main areas of clinical practice and research to develop the care of smokers with cancer. (i) Telling facts: smoking impacts on the survival and on the outcomes of surgery, chemo-, radio- and biological therapies. The aim of our intervention was to enable patients to make informed choices about smoking. (ii) Offering sensitive and effective smoking cessation like an instrument of patient empowerment to motivate change in smoker patient lifestyle. (iii) Assisting smoker patients if they develop acute nicotine withdrawal symptoms. Smoking care and nicotine replacement therapy can support temporary abstinence during the inpatient stay and providing patients with an opportunity for smoking cessation can prompt a future permanent quit attempt. Comprehensive cancer centers must act like a promoter of a better smokers' care, applying guidelines to their reality and try to do more research on smokers' needs and on the resources to assist them. Only the alliance between victims of smoking addiction and health personnel can give a chance against the tobacco epidemic.


Subject(s)
Neoplasms/psychology , Smoking Cessation/methods , Behavior Therapy , Humans , Smoking Cessation/psychology
7.
G Chir ; 31(11-12): 497-501, 2010.
Article in Italian | MEDLINE | ID: mdl-21232191

ABSTRACT

The incidence of gastrointestinal complications in renal transplant recipients is relatively high while about 10% is related to acute abdomen. Data concerning gastrointestinal (GI) complications were reported in literature mainly from referral center studies. A multicenter retrospectively survey was performed in Lazio, Italy, in order to evaluate the incidence of acute abdomen in renal transplant recipients observed to the emergency departments of not referral transplantation centers. Clinical and demographic findings regarding 14 patients who experienced acute abdomen between February 2005 and Dicember 2008 have been collected. The following data was investigated: etiology, diagnostic workup, duration of symptoms, elapsed time between admission and emergency operation if performed, morbility and mortality. The severity of disease at presentation was assessed by mean of the Acute Physiology and Chronic Health Evaluation score (APACHE II). Acute abdomen was due to pancreatitis in three patients (23.1%); to cholecystitis in three (23.1%); to acute diverticolitis with colon perforation in two patients (15.4%); to acute appendicitis in two (15.4%) and to intestinal obstruction in 2 patients (15.4%). Small bowel perforation was observed in two patients (15.4%) which one case, upon pathological examination, showed malignant lymphoma. The mean APACHE II score was 14.0 ± 5.9. Ten patients (71.4%) were submitted to surgery. Overall mortality and morbidity were 35% and 42% respectively. Statistical analysis showed admission APACHE II score (p<0.01), duration of symptoms (p<0.05), and total time elapsed between the onset of symptoms and treatment (p<0.04) as factors significantly related to mortality.


Subject(s)
Abdomen, Acute/epidemiology , Abdomen, Acute/surgery , Intensive Care Units , Kidney Transplantation , APACHE , Abdomen, Acute/diagnosis , Abdomen, Acute/etiology , Abdomen, Acute/mortality , Adult , Aged , Female , Gastrointestinal Diseases/complications , Health Surveys , Humans , Incidence , Italy/epidemiology , Kidney Transplantation/adverse effects , Kidney Transplantation/mortality , Lymphoma/complications , Male , Middle Aged , Referral and Consultation , Retrospective Studies , Risk Factors , Severity of Illness Index , Survival Rate
8.
Nat Commun ; 11(1): 5957, 2020 Nov 24.
Article in English | MEDLINE | ID: mdl-33235190

ABSTRACT

Metals and polymers are dissimilar materials in terms of their physicochemical properties, but complementary in terms of functionality. As a result, metal-organic structures can introduce a wealth of novel applications in small-scale robotics. However, current fabrication techniques are unable to process three-dimensional metallic and polymeric components. Here, we show that hybrid microstructures can be interlocked by combining 3D lithography, mold casting, and electrodeposition. Our method can be used to achieve complex multi-material microdevices with unprecedented resolution and topological complexity. We show that metallic components can be combined with structures made of different classes of polymers. Properties of both metals and polymers can be exploited in parallel, resulting in structures with high magnetic responsiveness, elevated drug loading capacity, on-demand shape transformation, and elastic behavior. We showcase the advantages of our approach by demonstrating new microrobotic locomotion modes and controlled agglomeration of swarms.

10.
J Exp Clin Cancer Res ; 36(1): 104, 2017 08 03.
Article in English | MEDLINE | ID: mdl-28774348

ABSTRACT

BACKGROUND: Ferritin plays a central role in the intracellular iron metabolism; the molecule is a nanocage of 24 subunits of the heavy and light types. The heavy subunit (FHC) is provided of a ferroxidase activity and thus performs the key transformation of iron in a non-toxic form. Recently, it has been shown that FHC is also involved in additional not iron-related critical pathways including, among the others, p53 regulation, modulation of oncomiRNAs expression and chemokine signalling. Epithelial to mesenchymal transition (EMT) is a cellular mechanism by which the cell acquires a fibroblast-like phenotype along with a decreased adhesion and augmented motility. In this work we have focused our attention on the role of the FHC on EMT induction in the human cell lines MCF-7 and H460 to elucidate the underlying molecular mechanisms. METHODS: Targeted silencing of the FHC was performed by lentiviral-driven shRNA strategy. Reconstitution of the FHC gene product was obtained by full length FHC cDNA transfection with Lipofectamine 2000. MTT and cell count assays were used to evaluate cell viability and proliferation; cell migration capability was assayed by the wound-healing assay and transwell strategy. Quantification of the CXCR4 surface expression was performed by flow cytometry. RESULTS: Experimental data indicated that FHC-silenced MCF-7 and H460 cells (MCF-7shFHC, H460shFHC) acquire a mesenchymal phenotype, accompanied by a significant enhancement of their migratory and proliferative capacity. This shift is coupled to an increase in ROS production and by an activation of the CXCR4/CXCL12 signalling pathway. We present experimental data indicating that the cytosolic increase in ROS levels is responsible for the enhanced proliferation of FHC-silenced cells, while the higher migration rate is attributable to a dysregulation of the CXCR4/CXCL12 axis. CONCLUSIONS: Our findings indicate that induction of EMT, increased migration and survival depend, in MCF-7 and H460 cells, on the release of FHC control on two pathways, namely the iron/ROS metabolism and CXCR4/CXCL12 axis. Besides constituting a further confirmation of the multifunctional nature of FHC, this data also suggest that the analysis of FHC amount/function might be an important additional tool to predict tumor aggressiveness.


Subject(s)
Apoferritins/metabolism , Chemokine CXCL12/metabolism , Receptors, CXCR4/metabolism , Apoferritins/genetics , Breast Neoplasms/metabolism , Breast Neoplasms/pathology , Carcinoma, Non-Small-Cell Lung/metabolism , Carcinoma, Non-Small-Cell Lung/pathology , Cell Line, Tumor , Cell Proliferation/physiology , Epithelial-Mesenchymal Transition , Female , Gene Silencing , Humans , Lung Neoplasms/metabolism , Lung Neoplasms/pathology , MCF-7 Cells , RNA, Small Interfering/administration & dosage , RNA, Small Interfering/genetics , Transfection
11.
Neuroscience ; 138(4): 1161-70, 2006.
Article in English | MEDLINE | ID: mdl-16427207

ABSTRACT

Considerable evidence supports the role of oxidative stress in the pathogenesis of Alzheimer's disease. One hallmark of Alzheimer's disease is the accumulation of amyloid beta-peptide, which invokes a cascade of oxidative damage to neurons that can eventually result in neuronal death. Amyloid beta-peptide is the main component of senile plaques and generates free radicals ultimately leading to neuronal damage of membrane lipids, proteins and nucleic acids. Therefore, interest in the protective role of different antioxidant compounds has been growing for treatment of Alzheimer's disease and other oxidative stress-related disorders. Among different antioxidant drugs, much interest has been devoted to "thiol-delivering" compounds. Tricyclodecan-9-yl-xanthogenate is an inhibitor of phosphatidylcholine specific phospholipase C, and recent studies reported its ability to act as a glutathione-mimetic compound. In the present study, we investigate the in vivo ability of tricyclodecan-9-yl-xanthogenate to protect synaptosomes against amyloid beta-peptide-induced oxidative stress. Gerbils were injected i.p. with tricyclodecan-9-yl-xanthogenate or with saline solution, and synaptosomes were isolated from the brain. Synaptosomal preparations isolated from tricyclodecan-9-yl-xanthogenate injected gerbils and treated ex vivo with amyloid beta-peptide (1-42) showed a significant decrease of oxidative stress parameters: reactive oxygen species levels, protein oxidation (protein carbonyl and 3-nitrotyrosine levels) and lipid peroxidation (4-hydroxy-2-nonenal levels). Our results are consistent with the hypothesis that modulation of free radicals generated by amyloid beta-peptide might represent an efficient therapeutic strategy for treatment of Alzheimer's disease and other oxidative-stress related disorders. Based on the above data, we suggest that tricyclodecan-9-yl-xanthogenate is a potent antioxidant and could be of importance for the treatment of Alzheimer's disease and other oxidative stress-related disorders.


Subject(s)
Alzheimer Disease/drug therapy , Amyloid beta-Peptides/antagonists & inhibitors , Bridged-Ring Compounds/pharmacology , Nerve Degeneration/drug therapy , Oxidative Stress/drug effects , Peptide Fragments/antagonists & inhibitors , Thiones/pharmacology , Aldehydes/antagonists & inhibitors , Aldehydes/metabolism , Alzheimer Disease/metabolism , Alzheimer Disease/physiopathology , Amyloid beta-Peptides/toxicity , Animals , Antioxidants/pharmacology , Antioxidants/therapeutic use , Brain/drug effects , Brain/metabolism , Bridged-Ring Compounds/therapeutic use , Disease Models, Animal , Free Radicals/antagonists & inhibitors , Free Radicals/metabolism , Gerbillinae , Lipid Peroxidation/drug effects , Lipid Peroxidation/physiology , Male , Nerve Degeneration/metabolism , Nerve Degeneration/physiopathology , Neurons/drug effects , Neurons/metabolism , Norbornanes , Oxidative Stress/physiology , Peptide Fragments/toxicity , Reactive Oxygen Species/antagonists & inhibitors , Reactive Oxygen Species/metabolism , Synaptosomes , Thiocarbamates , Thiones/therapeutic use , Type C Phospholipases/antagonists & inhibitors , Type C Phospholipases/metabolism , Tyrosine/analogs & derivatives , Tyrosine/antagonists & inhibitors , Tyrosine/metabolism
12.
Biochim Biophys Acta ; 561(1): 206-14, 1979 Jan 26.
Article in English | MEDLINE | ID: mdl-217436

ABSTRACT

Thiaisoleucine is an isoleucine analogue having the gamma-methylene group of the valerianic carbon chain substituted by a sulphur atom. It has been demonstrated that thiaisoleucine is activated and transferred to tRNAIle by rat liver aminoacyl-tRNA synthetase and inhibits isoleucine incorporation into polypeptides in protein synthesizing systems from rat liver or rabbit reticulocytes, whereas it does not affect either leucine incorporation or ribosome run-off or polypeptide chain elongation rate. All tests were performed in comparison with O-methyl-threonine, an isoleucine analogue with the gamma-methylene group substituted by an oxygen atom. In all the reactions studied, both thiaisoleucine and O-methyl-threonine act as competitive inhibitors of isoleucine. With respect to O-methyl-threonine, thiaisoleucine shows higher activity as an isoleucine inhibitor.


Subject(s)
Amino Acyl-tRNA Synthetases/metabolism , Isoleucine/analogs & derivatives , Protein Biosynthesis , Adenosine Triphosphate/metabolism , Animals , Diphosphates/metabolism , Isoleucine/metabolism , Kinetics , RNA, Transfer, Amino Acyl/biosynthesis , Rabbits , Rats , Structure-Activity Relationship , Substrate Specificity , Threonine/analogs & derivatives , Threonine/metabolism
13.
Biochim Biophys Acta ; 1243(1): 71-7, 1995 Jan 18.
Article in English | MEDLINE | ID: mdl-7827110

ABSTRACT

Opioid peptides can be converted by tyrosinase into melanin-like compounds, in which the peptide moiety is retained. Such pigments, named opio-melanins, exhibit a characteristic absorption spectrum with a maximum at about 330 nm and a different solubility behaviour with respect to dopa-melanin, being completely soluble in hydrophylic solvents at neutral and basic pH. Opio-melanins precipitate in aqueous solutions below pH 5.0, and show apparent pKa values of 3.1, 3.6 and 4.4 for Tyr-Gly-melanin, Tyr-Gly-Gly-melanin and leuenk-melanin, respectively. The concomitant oxidation of dopa and opioid peptides by tyrosinase produces mixed polymers, showing the distinctive absorption peak at 330 nm. In the dark, in the pH range 5.5-7.0 the pigments are completely stable, whereas H2O2 addition provokes a slight degradation. At higher pH values or under simulated solar illumination with or without hydrogen peroxide, bleaching occurs more rapidly than in dopa-melanin. Upon photoirradiation the absorption spectrum of opio-melanins undergoes a marked variation, the peak at 330 nm being replaced by a broad shoulder in the range 280-350 nm. The absorption spectra of native and bleached pigments and the extent of opio-melanins degradation by bleaching agents, confirm the hypothesis that the different initial structure of the precursors accounts for a final diverse polymeric architecture of these pigments with respect to dopa-melanin.


Subject(s)
Melanins/chemistry , Opioid Peptides/chemistry , Amino Acid Sequence , Darkness , Hydrogen Peroxide/pharmacology , Melanins/radiation effects , Molecular Sequence Data , Monophenol Monooxygenase/metabolism , Opioid Peptides/drug effects , Opioid Peptides/radiation effects , Photolysis , Polymers/chemistry , Polymers/radiation effects , Spectrophotometry , Sunlight
14.
Biochim Biophys Acta ; 454(2): 298-308, 1976 Dec 01.
Article in English | MEDLINE | ID: mdl-187234

ABSTRACT

Selenalysine is a lysine analog having the gamma-methylene group substituted by a selenium atom. It has been demonstrated that selenalysine is activated and transferred to tRNAlys by either Escherichia coli or rat liver aminoacyl-tRNA synthetases, and inhibits lysine incorporation into polypeptides in protein-synthesizing systems from E. coli, rat liver or rabbit reticulocytes. All tests were performed in comparison with thialysine, a lysine analog having the gamma-methylene group substituted by a sulfur atom. In all the reactions studied, both thialysine and selenalysine act as competitive inhibitors of lysine. With respect to thialysine, selenalysine act as competitive inhibitors of lysine. With respect to thialysine, selenalysine shows a slightly lower activity as lysine inhibitor.


Subject(s)
Lysine/analogs & derivatives , Protein Biosynthesis , Selenium , Adenosine Triphosphate/metabolism , Animals , Binding, Competitive , Cell-Free System , Diphosphates/metabolism , Escherichia coli/metabolism , Kinetics , Leucine/metabolism , Liver/metabolism , Lysine/metabolism , Lysine-tRNA Ligase/metabolism , Microsomes, Liver/metabolism , Peptide Biosynthesis , Phenylalanine/metabolism , Rabbits , Rats , Reticulocytes/metabolism , Ribosomes/metabolism
15.
Biochim Biophys Acta ; 678(2): 165-71, 1981 Dec 04.
Article in English | MEDLINE | ID: mdl-6797476

ABSTRACT

The presence of selenalysine in the culture medium at concentration ranging from 0.05 to 0.3 mM inhibits Escherichia coli growth rate and cell viability. The inhibition of cell growth rate can be imputed to the inhibition of protein synthesis and can be only partially reverted by lysine. Selenalysine is incorporated into cellular proteins in substitution of and in competition with lysine, reaching the value of about 1% as molar fraction with respect to the total amino acids, and substituting up to 14% of protein lysine. The effect of selenalysine on cell viability can be correlated to the extent of its incorporation into proteins, and can be completely reverted by lysine. However, substitution up to 5% of protein lysine by selenalysine does not affect the viability, thus indicating that some degree of substitution can be well tolerated by the cell.


Subject(s)
Bacterial Proteins/biosynthesis , Escherichia coli/growth & development , Lysine/analogs & derivatives , Organoselenium Compounds , Selenium/metabolism , Cell Survival/drug effects , Escherichia coli/metabolism , Kinetics , Lysine/metabolism , Lysine/pharmacology , Selenium/pharmacology
16.
Biochim Biophys Acta ; 606(2): 347-52, 1980 Feb 29.
Article in English | MEDLINE | ID: mdl-6243985

ABSTRACT

Beta-Selenaproline, a proline analog having the beta-methylene group substituted by a selenium atom, has been tested in ATP-PPi exchange reaction catalyzed by either Escherichia coli or rat liver aminoacyl-tRNA synthetases. It has been shown that with both enzymatic systems beta-selenaproline does not give rise to ATP-PPi exchange, but specifically inhibits proline activation. The inhibition is of fully competitive type and the Ki values, lower than the Km values for proline, show that beta-selenaproline binds to the synthetases with high affinity. The inability to form the complex with AMP, taking into account also the behavior of gamma-selenaproline and other proline analogs, has been ascribed to the presence of the selenium atom in the beta-position.


Subject(s)
Organoselenium Compounds , Proline/analogs & derivatives , Proline/metabolism , Selenium/pharmacology , Adenosine Triphosphate/metabolism , Amino Acyl-tRNA Synthetases/metabolism , Animals , Diphosphates/metabolism , Escherichia coli/enzymology , Kinetics , Liver/enzymology , Proline/pharmacology , Rats , Selenium/metabolism
17.
Biochim Biophys Acta ; 564(2): 311-21, 1979 Sep 27.
Article in English | MEDLINE | ID: mdl-385056

ABSTRACT

Thiazolidine-2-carboxylic acid, or beta-thiaproline, is a proline analog in which the beta methylene group of proline is substituted by a sulfur atom. It has been deomonstrated that beta-thiaproline is activated and transferred to tRNAPro by Escherichia coli and rat liver aminoacyl-tRNA synthetases, and inhibits proline incorporation into polypeptides in protein synthesizing systems from E. coli, rat liver or rabbit reticulocytes. In mammalian systems beta-thiaproline inhibits also leucine incorporation; in rabbit reticulocyte lysate it inhibits ribosome run-off. Both these effects may be explained by the fact that beta-thiaproline once incorporated into the growing polypeptide chain impairs its further elongation, as shown by experiments made with puromycin. All tests were performed in comparison with thiazolidine-4-carboxylic acid, or gamma-thiaproline, another proline analog having the gamma methylene group substituted by a sulfur atom; it was shown that in all the reactions studied both compounds act as competitive inhibitors of proline. Some differences in the effects of the two analogs have been evidenced: in almost all the reactions and mainly in the whole protein synthesizing systems, beta-thiaproline shows an higher inhibitory activity.


Subject(s)
Amino Acyl-tRNA Synthetases/metabolism , Proline/analogs & derivatives , Protein Biosynthesis/drug effects , Amino Acids, Sulfur/pharmacology , Animals , Escherichia coli/enzymology , Kinetics , Liver/enzymology , Proline/pharmacology , Puromycin/pharmacology , RNA, Transfer/metabolism , Rabbits , Rats , Reticulocytes/enzymology , Thiazolidines
18.
Biochim Biophys Acta ; 1525(1-2): 43-9, 2001 Feb 16.
Article in English | MEDLINE | ID: mdl-11342252

ABSTRACT

The oxidation of opioid peptides by tyrosinase in the presence of an excess of a thiol gives rise to cysteinyldopa derivatives. The major products arising from the reaction between Leu-enkephalin and cysteine are represented by 5-S-cysteinyldopaenkephalin (5-CDenk) and 2-S-cysteinyldopaenkephalin (2-CDenk). The interaction of 5-CDenk and 2-CDenk with reactive oxygen species (ROS) has been studied. These compounds are able to scavenge superoxide anion, hydroxyl and peroxyl radicals as well as to reduce the lipid peroxidation rate induced by ABAP. The scavenging activities in all instances are dose-dependent. In some cases CDenks are more active than compounds recognized as strong radical scavengers, such as Trolox and mannitol. As a result of the action of the Fenton system, the CDenks (as well as the Enks) are oxidized into pigmented derivatives. The possible implications of the interaction of CDenks and Enks with ROS on melanization process in Parkinson's disease are discussed.


Subject(s)
Enkephalins/metabolism , Reactive Oxygen Species/metabolism , Animals , Enkephalins/chemistry , Free Radical Scavengers/metabolism , Humans , Hydroxyl Radical/metabolism , In Vitro Techniques , Lipid Peroxidation , Melanins/biosynthesis , Oxidation-Reduction , Parkinson Disease/metabolism , Peroxides/metabolism , Superoxides/metabolism
19.
Biochim Biophys Acta ; 1199(2): 123-9, 1994 Mar 02.
Article in English | MEDLINE | ID: mdl-7907228

ABSTRACT

Opioid peptides are converted by mushroom tyrosinase into melanin-like compounds retaining the peptide moiety (opio-melanins). Opio-melanins, owing to the presence of the linked aminoacids and in contrast with DOPA-melanin, are soluble compounds. The enkephalin-generated melanins are cleaved by carboxypeptidase A and pronase whereas aminopeptidase M cannot remove aminoacids from the pigment. Enkephalins, as well as other opioid peptides, (alpha-endorphin, kyotorphin, esorphins) if oxidized in presence of DOPA and tyrosinase are readily incorporated into DOPA-melanin. The resulting mixed-melanins (opio-melanin + DOPA-melanin) can be solubilized in hydrophilic solvents. Melanin from leu-enkephalin exhibits paramagnetism as evidenced by an EPR spectrum identical to that of DOPA-melanin, but unlike the latter pigment, it does not appear to oxidize NADH, probably for the presence of the peptide moiety that exerts a hampering effect on the oxidizing capacity.


Subject(s)
Endorphins/chemistry , Melanins/chemistry , Amino Acid Sequence , Aminopeptidases/metabolism , Basidiomycota/enzymology , CD13 Antigens , Carboxypeptidases/metabolism , Carboxypeptidases A , Dihydroxyphenylalanine/metabolism , Electron Spin Resonance Spectroscopy , Endorphins/metabolism , Enkephalins/chemistry , Enkephalins/metabolism , Kinetics , Melanins/metabolism , Molecular Sequence Data , Monophenol Monooxygenase/metabolism , NAD/metabolism , Oxidation-Reduction , Pronase/metabolism , Solubility
20.
Free Radic Biol Med ; 26(3-4): 446-53, 1999 Feb.
Article in English | MEDLINE | ID: mdl-9895237

ABSTRACT

5,6-Dihydroxyindole (DHI) and 5,6-dihydroxyindole-2-carboxylic acid (DHICA), which are important intermediates in melanogenesis, can be converted into the corresponding melanin pigments by the action of the lipoxygenase/H2O2 system. Kinetic and HPLC analyses indicate that both DHI and DHICA are good substrates for this enzymatic system. Enzyme activity on both substrates was measured in comparison with peroxidase and tyrosinase; the oxidizing behaviour of lipoxygenase is more similar to that of peroxidase rather than that of tyrosinase. The antioxidant properties of DHI- and DHICA-melanins have been investigated in comparison with other kinds of melanins. DHICA-melanin shows a more pronounced antioxidant effect than that of DHI-melanin and this behaviour can be ascribed to the different structure and solubility of the two pigments. The mixed polymer synthesized from DHI and DHICA is the most effective one. Some implications about the possible explanation of the above mentioned behaviour are discussed.


Subject(s)
Antioxidants/metabolism , Hydrogen Peroxide/metabolism , Indoles/metabolism , Lipoxygenase/metabolism , Melanins/biosynthesis , Catalysis , Chromatography, High Pressure Liquid , Free Radicals , Kinetics , Oxidation-Reduction
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