354 research outputs found
Cloning, expression and purification of the complete domain of the η-carbonic anhydrase from Plasmodium falciparum.
The antimalarial drugs are of fundamental importance in the control of malaria, especially for the lack of efficient treatments and acquired resistance to the existing drugs. For this reason, there is a continuous work in identifying novel, less toxic and effective chemotherapies as well as new therapeutic targets against the causative agents of malaria. In this context, a superfamily of metalloenzymes named carbonic anhydrases (CAs, EC 4.2.1.1) has aroused a great interest as druggable enzymes to limit the development of Plasmodium falciparum gametocytes. CAs catalyze a common reaction in all life domains, the carbon dioxide hydration to bicarbonate and protons (CO2 + H2O HCO3- + H+). P. falciparum synthesizes pyrimidines de novo starting from HCO3-, which is generated from CO2 through the action of the ?-CA identified in the genome of the protozoan. Here, we propose a procedure for the preparation of a wider portion of the protozoan ?-CA, named PfCAdom (358 amino acid residues), with respect to the truncated form prepared by Krungkrai et al. (PfCA1, 235 amino acid residues). The results evidenced that the recombinant PfCAdom, produced as a His-tag fusion protein, was 2.7 times more active with respect the truncated form PfCA1
Catechols: a new class of carbonic anhydrase inhibitors
Catechols adopt a peculiar binding mode to the CA active site which involves both the zinc bound water molecule and the "deep water"
Protective role of carbonic anhydrases III and VII in cellular defense mechanisms upon redox unbalance
Under oxidative stress conditions, several constitutive cellular defense systems are activated, which involve both enzymatic systems
and molecules with antioxidant properties such as glutathione and vitamins. In addition, proteins containing reactive sulfhydryl
groups may eventually undergo reversible redox modifications whose products act as protective shields able to avoid further
permanent molecular oxidative damage either in stressful conditions or under pathological circumstances. After the recovery of
normal redox conditions, the reduced state of protein sulfhydryl groups is restored. In this context, carbonic anhydrases (CAs)
III and VII, which are human metalloenzymes catalyzing the reversible hydration of carbon dioxide to bicarbonate and proton,
have been identified to play an antioxidant role in cells where oxidative damage occurs. Both proteins are mainly localized in
tissues characterized by a high rate of oxygen consumption, and contain on their molecular surface two reactive cysteine
residues eventually undergoing S-glutathionylation. Here, we will provide an overview on the molecular and functional features
of these proteins highlighting their implications into molecular processes occurring during oxidative stress conditions
Risk perception, knowledge about SARS-CoV-2, and perception towards preventive measures in Italy: a nationwide cross-sectional study
Introduction: After COVID-19 outbreak, governments adopted several containment measures. Risk perception and knowledge may play a crucial role since they can affect compliance with preventive measures. This study aimed to explore the extent and the associated factors of risk perception, knowledge regarding SARS-CoV2, and perception towards preventive measures among the Italian population.
Methods: A nationwide cross-sectional study involving adults was conducted in April-May 2021: an online survey was distributed through social media. The outcomes were: Knowledge Score (KS) (0 to 100%: higher scores correspond to higher COVID-19-related knowledge); Risk Perception Score (RPS) (1 to 4: higher values indicate higher concern); Preventive measures Perception Score (PPS) (1 to 4: higher values indicate higher confidence). Multivariable regression models were performed.
Results: A total of 1120 participants were included. Median KS was 79.5% (IQR=72.7%-86.4%). Lower education and poor economic conditions were negatively associated with the KS. Median RPS was 2.8 (IQR=2.4-3.2). Female gender, sharing house with a fragile person, suffering from a chronic disease, having a family member/close friend who contracted SARS-CoV-2 infection were positively associated with the RPS. Median PPS was 3.1 (IQR=2.8-3.4). Lower educational level was negatively associated with the PPS. Vaccine hesitancy was negatively associated with all three outcomes. The three scores were positively associated with each other.
Conclusions: Fair levels of knowledge, risk perception and perception towards preventive measures were reported. Reciprocal relationships between the outcomes and a relevant relationship with vaccine hesitancy were highlighted. Further investigations should be focused on studying underlying determinants and consequences
Insights into the role of reactive sulfhydryl groups of Carbonic Anhydrase III and VII during oxidative damage
Carbonic anhydrases (CAs) III and VII are two cytosolic isoforms of the α-CA family which catalyze the physiological reaction of carbon dioxide hydration to bicarbonate and proton. Despite these two enzymes share a 49% sequence identity and present a very similar three-dimensional structure, they show profound differences when comparing the specific activity for CO2 hydration reaction, with CA VII being much more active than CA III. Recently, CA III and CA VII have been proposed to play a new role as scavenger enzymes in cells where oxidative damage occurs. Here, we will examine functional and structural features of these two isoforms giving insights into their newly proposed protective role against oxidative stress
A Substrate-induced Switch in the Reaction Mechanism of a Thermophilic Esterase KINETIC EVIDENCES AND STRUCTURAL BASIS
The reaction mechanism of the esterase 2 (EST2) from Alicyclobacillus acidocaldarius was studied at the kinetic and structural level to shed light on the mechanism of activity and substrate specificity increase previously observed in its double mutant M211S/R215L. In particular, the values of kinetic constants (k1, k(-1), k2, and k3) along with activation energies (E1, E(-1), E2, and E3) were measured for wild type and mutant enzyme. The previously suggested substrate-induced switch in the reaction mechanism from kcat=k3 with a short acyl chain substrate (p-nitrophenyl hexanoate) to kcat=k2 with a long acyl chain substrate (p-nitrophenyl dodecanoate) was validated. The inhibition afforded by an irreversible inhibitor (1-hexadecanesulfonyl chloride), structurally related to p-nitrophenyl dodecanoate, was studied by kinetic analysis. Moreover the three-dimensional structure of the double mutant bound to this inhibitor was determined, providing essential information on the enzyme mechanism. In fact, structural analysis explained the observed substrate-induced switch because of an inversion in the binding mode of the long acyl chain derivatives with respect to the acyl- and alcohol-binding sites
2-Mercaptobenzoxazoles: a class of carbonic anhydrase inhibitors with a novel binding mode to the enzyme active site.
2-Mercaptobenzoxazole represents an interesting lead compound alternative to the classical sulfonamides for the development of selective carbonic anhydrase inhibitors
Efficacy of Low-Dose Paroxetine for the Treatment of Hot Flushes in Surgical and Physiological Postmenopausal Women: Systematic Review and Meta-Analysis of Randomized Trials
Background and Objectives: Hot flushes and sleep disturbances are the most common vasomotor symptoms (VMS) reported by postmenopausal women. Hormonal treatment is to date referred to as the gold standard approach but not suitable for all the patients. Alternative treatments are needed in case of a contraindication to menopausal hormone therapy (MHT), adverse side effects, and poor compliance. Paroxetine salt is the only nonhormonal medication approved by the US Food and Drug Administration for the management of VMS. Nonetheless, few trials with low consensus are available about this topic. In this review, we aimed to evaluate the efficacy of low-dose paroxetine therapy in the treatment of vasomotor hot flushes and night sleep disturbances in postmenopausal women. Materials and Methods: We performed an electronic search from the beginning of all databases to July 2019. All results were then limited to a randomized trial. Restrictions for language or geographic location were not utilized. Inclusion criteria were randomized clinical trials of physiological or surgical postmenopausal women experiencing hot flushes and sleep disturbances who were randomized to either low-dose paroxetine or placebo (i.e., formulations without active ingredients). The primary outcome evaluated was the mean weekly reduction of hot flushes. Results: Five randomized clinical trials, including 1482 postmenopausal women, were analyzed. Significant heterogeneity (I2 = 90%) between studies was noted. Hot flushes episodes were significantly reduced in the treatment arm compared to placebo (mean difference (MD) -7.97 [-10.51, -5.92] episodes/week). Results on the improvement on sleep were limited by being reported in only two studies; however, no significant reduction of night-time awakenings was observed (MD, -0.40 awakenings/night [-1.38, 0.58 CI]). Conclusions: Low-dose paroxetine is an effective treatment for vasomotor menopause symptoms, including hot flushes
From Alpine-type sulfides to nonsulfides in the Gorno Zn project (Bergamo, Italy)
Recent exploration of the Gorno Zn-Pb-Ag deposit in northern Italy identified 3.3 Mt of sulfides at 4.9% Zn, 1.3% Pb, and 27.2 g/t Ag (indicated+inferred resources), and a further mineralized nucleus of mixed sulfides-nonsulfides in the Val Vedra area, currently under evaluation. The ores are hosted in Triassic limestone and shale. Sulfides (sphalerite, Ag-bearing galena, minor pyrite, and chalcopyrite) paragenetically follow Mn-Fe-bearing saddle dolomite and sparry calcite. The mineral association, and the carbon and oxygen isotope ratios of the sparry calcite (avg. δ13C = 1.0 ± 0.6‰ V-PDB; avg. δ18O = 19.63 ± 1.25‰ V-SMOW), are in agreement with precipitation from hydrothermal fluids in a deep burial setting. Sulfide emplacement occurred before the Alpine orogeny, likely during the Early-Middle Jurassic, in analogy to other Alpine-type deposits. The nonsulfide ore formed at the expense of sulfides, and mainly consists of smithsonite, hydrozincite, hemimorphite, and cerussite. The C-O-isotope values of the early generations of Zn-carbonates are characterized by δ18O between 24.1 and 26.8‰ V-SMOW and δ13C ratios between − 3.1 and 1.7‰ V-PDB. The later generations have lower δ18O (21.9 to 23.9‰) and lower δ13C (− 6.2 to − 3.9‰). These compositions, as those measured on cerussite (δ13C = −6.3 and − 7.7‰; δ18O = 14.0 and 15.3‰), agree with the formation of the nonsulfides in a supergene environment, under climatic conditions warmer than today. The δ18O decrease from early to late generations suggests progressive involvement of meteoric water sourced from higher altitudes. These characteristics indicate that the nonsulfides formed during the exhumation of the Gorno area from Miocene to Pliocene
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