Curcumin is recognized for its diverse biological activities, including the ability to induce apoptosis and ferroptosis. Therefore, it represents a promising candidate for the development of new compounds with neuroprotective and anticancer properties. In order to synthesize mimics with improved pharmacokinetic properties (better solubility and stability than curcumin) here, we present the design and synthesis of novel curcumin analogues named Ethylphosphonate-based curcumin mimics (EPs), which preserve the pharmacophoric features of curcumin. New EP mimics were synthesized by tyrosol- and melatonin-based building blocks using an orthogonal protection approach of the different precursors' OH functions with good yields and in a few steps. Comparative screenings of the cytotoxic and cytoprotective properties (curcumin was used as a reference compound) were carried out on all new mimics in different cell lines (HeLa, A375, WM266, MDA-MB-231, LX2, and HDF). Assays with inhibitors of ferroptosis (Ferrostatin-1, Fer-1) and apoptosis (Quinoline-Val-Asp-difluorophenoxymethyl ketone, Q-VD), in combination with curcumin, suggested the specific cell death pathway (apoptotic or ferroptotic) of EPs, depending on the aromatic moieties contained in them. Interestingly, EP4 exhibited substantial cytotoxic effects against various human cancer cell lines (HeLa, A375, WM266) while sparing normal cells (HDFs). EP4 displayed a five-times-higher toxicity in triple-negative MDA-MB-231 and LX2 stellate cells than curcumin. The cytotoxicity exerted by EP4 involves only an apoptotic mechanism, contrary to curcumin, which exerts both apoptotic and ferroptotic effects. Additionally, EP4 was also found to be a very potent inhibitor of the ubiquitin-activating enzyme E1, reinforcing the anticancer potential of this compound. Furthermore, EP2 possesses high antioxidant properties, efficiently protects against cell death by ferroptosis, and inhibits the amyloid aggregation involved in AD.

• Klíčová slova
• Alzheimer’s disease, apoptosis, cancer, curcumin mimics, ferroptosis, oxidative stress,
• Publikační typ
• časopisecké články MeSH

In the carnivorous plant Venus flytrap (Dionaea muscipula), the sequence of events after prey capture resembles the well-known plant defence signalling pathway in response to pathogen or herbivore attack. Here, we used wounding to mimic prey capture to show the similarities and differences between botanical carnivory and plant defence mechanisms. We monitored movement, electrical signalling, jasmonate accumulation and digestive enzyme secretion in local and distal (systemic) traps in response to prey capture, the mechanical stimulation of trigger hairs and wounding. The Venus flytrap cannot discriminate between wounding and mechanical trigger hair stimulation. Both induced the same action potentials, rapid trap closure, hermetic trap sealing, the accumulation of jasmonic acid (JA) and its isoleucine conjugate (JA-Ile), and the secretion of proteases (aspartic and cysteine proteases), phosphatases and type I chitinase. The jasmonate accumulation and enzyme secretion were confined to the local traps, to which the stimulus was applied, which correlates with the propagation of electrical signals and the absence of a systemic response in the Venus flytrap. In contrast to plant defence mechanisms, the absence of a systemic response in carnivorous plant may represent a resource-saving strategy. During prey capture, it could be quite expensive to produce digestive enzymes in the traps on the plant without prey.

• Klíčová slova
• Venus flytrap, action potential, carnivorous plant, defence, digestive enzyme, electrical signal, jasmonic acid (JA), systemic response,
• MeSH
• chitinasy metabolismus   MeSH
• cyklopentany metabolismus   MeSH
• Droseraceae fyziologie   MeSH
• enzymy metabolismus   MeSH
• hmyz MeSH
• oxylipiny metabolismus   MeSH
• rostlinné proteiny metabolismus   MeSH
• signální transdukce MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• chitinasy MeSH
• cyklopentany MeSH
• enzymy MeSH
• jasmonic acid MeSH Prohlížeč
• oxylipiny MeSH
• rostlinné proteiny MeSH

Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are well recognized for playing a dual role, since they can be either deleterious or beneficial to biological systems. An imbalance between ROS production and elimination is termed oxidative stress, a critical factor and common denominator of many chronic diseases such as cancer, cardiovascular diseases, metabolic diseases, neurological disorders (Alzheimer's and Parkinson's diseases), and other disorders. To counteract the harmful effects of ROS, organisms have evolved a complex, three-line antioxidant defense system. The first-line defense mechanism is the most efficient and involves antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx). This line of defense plays an irreplaceable role in the dismutation of superoxide radicals (O2•-) and hydrogen peroxide (H2O2). The removal of superoxide radicals by SOD prevents the formation of the much more damaging peroxynitrite ONOO- (O2•- + NO• → ONOO-) and maintains the physiologically relevant level of nitric oxide (NO•), an important molecule in neurotransmission, inflammation, and vasodilation. The second-line antioxidant defense pathway involves exogenous diet-derived small-molecule antioxidants. The third-line antioxidant defense is ensured by the repair or removal of oxidized proteins and other biomolecules by a variety of enzyme systems. This review briefly discusses the endogenous (mitochondria, NADPH, xanthine oxidase (XO), Fenton reaction) and exogenous (e.g., smoking, radiation, drugs, pollution) sources of ROS (superoxide radical, hydrogen peroxide, hydroxyl radical, peroxyl radical, hypochlorous acid, peroxynitrite). Attention has been given to the first-line antioxidant defense system provided by SOD, CAT, and GPx. The chemical and molecular mechanisms of antioxidant enzymes, enzyme-related diseases (cancer, cardiovascular, lung, metabolic, and neurological diseases), and the role of enzymes (e.g., GPx4) in cellular processes such as ferroptosis are discussed. Potential therapeutic applications of enzyme mimics and recent progress in metal-based (copper, iron, cobalt, molybdenum, cerium) and nonmetal (carbon)-based nanomaterials with enzyme-like activities (nanozymes) are also discussed. Moreover, attention has been given to the mechanisms of action of low-molecular-weight antioxidants (vitamin C (ascorbate), vitamin E (alpha-tocopherol), carotenoids (e.g., β-carotene, lycopene, lutein), flavonoids (e.g., quercetin, anthocyanins, epicatechin), and glutathione (GSH)), the activation of transcription factors such as Nrf2, and the protection against chronic diseases. Given that there is a discrepancy between preclinical and clinical studies, approaches that may result in greater pharmacological and clinical success of low-molecular-weight antioxidant therapies are also subject to discussion.

• Klíčová slova
• Antioxidant enzymes, Chronic disease, Enzyme mimics, Low-molecular antioxidants, Oxidative stress, ROS,
• MeSH
• anthokyaniny metabolismus   farmakologie   MeSH
• antioxidancia * farmakologie   metabolismus   MeSH
• chronická nemoc MeSH
• kyselina peroxydusitá farmakologie   MeSH
• lidé MeSH
• nádory * MeSH
• oxid dusnatý MeSH
• oxidační stres MeSH
• peroxid vodíku MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• superoxiddismutasa metabolismus   MeSH
• superoxidy MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• anthokyaniny MeSH
• antioxidancia * MeSH
• kyselina peroxydusitá MeSH
• oxid dusnatý MeSH
• peroxid vodíku MeSH
• reaktivní formy kyslíku MeSH
• superoxiddismutasa MeSH
• superoxidy MeSH

The conformational changes in a sugar moiety along the hydrolytic pathway are key to understand the mechanism of glycoside hydrolases (GHs) and to design new inhibitors. The two predominant itineraries for mannosidases go via O S2 →B2,5 →1 S5 and 3 S1 →3 H4 →1 C4 . For the CAZy family 92, the conformational itinerary was unknown. Published complexes of Bacteroides thetaiotaomicron GH92 catalyst with a S-glycoside and mannoimidazole indicate a 4 C1 →4 H5 /1 S5 →1 S5 mechanism. However, as observed with the GH125 family, S-glycosides may not act always as good mimics of GH's natural substrate. Here we present a cooperative study between computations and experiments where our results predict the E5 →B2,5 /1 S5 →1 S5 pathway for GH92 enzymes. Furthermore, we demonstrate the Michaelis complex mimicry of a new kind of C-disaccharides, whose biochemical applicability was still a chimera.

• Klíčová slova
• carbohydrates, conformations, enzymology, inhibitors, quantum mechanics,
• MeSH
• glykosidhydrolasy metabolismus   MeSH
• glykosidy * chemie   MeSH
• mannosidasy * chemie   MeSH
• molekulární konformace MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• C-glycoside MeSH Prohlížeč
• glykosidhydrolasy MeSH
• glykosidy * MeSH
• mannosidasy * MeSH

Hunting cycle of the carnivorous plant Venus flytrap (Dionaea muscipula Ellis) is comprised of mechanism for rapid trap closure followed by slow hermetical sealing and activation of gene expression responsible for digestion of prey and nutrient uptake. In the present study, we focus on the late phase of Venus's flytrap hunting cycle when mechanical stimulation of the prey ceases and is replaced by chemical cues. We used two nitrogen-rich compounds (chitin and protein) in addition to mechanostimulation to investigate the electrical and jasmonate signalling responsible for induction of enzyme activities. Chemical stimulation by BSA protein and chitin did not induce any additional spontaneous action potentials (APs). However, chemical stimulation by protein induced the highest levels of jasmonic acid (JA) and its isoleucine conjugate (JA-Ile) as well as the expression of studied gene encoding a cysteine protease (dionain). Although chitin is probably the first chemical agent which is in direct contact with digestive glands, presence of protein in the secured trap mimics the presence of insect prey best.

• Klíčová slova
• Action potential, Carnivorous plant, Chitinase, Digestive enzyme, Jasmonic acid, Protease, Venus flytrap,
• MeSH
• cyklopentany MeSH
• Droseraceae * MeSH
• oxylipiny MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• cyklopentany MeSH
• jasmonic acid MeSH Prohlížeč
• oxylipiny MeSH

The carnivorous pitcher plants of the genus Nepenthes usually attract, capture and digest arthropod prey to obtain mineral nutrients. But few members of the genus have evolved specialized nutrient sequestration strategies to acquire nitrogen from the faeces and urine of mutualistic mammals, which they attract. Because the plants obtain significant amounts of nitrogen in a more available form, we hypothesized that they have relaxed the production of digestive enzymes. If so, species that digest mammal faeces should show fewer digestive enzymes than closely related species that rely on arthropods. We tested this hypothesis by comparing digestive enzymes in 1) Nepenthes hemsleyana, whose pitchers serve as roosts for the mutualistic woolly bat Kerivoula hardwickii, which also defecate inside the pitchers, and 2) the close relative Nepenthes rafflesiana, a typical arthropod capturing species. To investigate the dynamics of aspartic proteases (nepenthesin I and II) and type III and IV chitinases in both species, we conducted qPCR, western blotting, mass spectrometry, and enzyme activity measurements. We found that mRNA in pitcher tissue and enzyme abundance in the digestive fluid is upregulated in both species in response to faeces and insect feeding. Contrary to our initial hypothesis, the final nepenthesin proteolytic activity in the digestive fluid is higher in response to faeces addition than to insect prey irrespective of Nepenthes species. This indicates that faeces can mimic arthropod prey triggering the production of digestive enzymes and N. hemsleyana retained capacity for production of them.

• Klíčová slova
• Bat, Carnivorous plant, Chitinase, Digestive enzyme, Nepenthes, Nepenthesin, Pitcher plants, Proteinase, Western blot,
• MeSH
• dusík MeSH
• Magnoliopsida * MeSH
• masožravé rostliny * MeSH
• organické látky MeSH
• symbióza MeSH
• živiny MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• dusík MeSH
• nepenthe MeSH Prohlížeč
• organické látky MeSH

Enzymes are the natural catalysts that execute biochemical reactions upholding life. Their natural effectiveness has been fine-tuned as a result of millions of years of natural evolution. Such catalytic effectiveness has prompted the use of biocatalysts from multiple sources on different applications, including the industrial production of goods (food and beverages, detergents, textile, and pharmaceutics), environmental protection, and biomedical applications. Natural enzymes often need to be improved by protein engineering to optimize their function in non-native environments. Recent technological advances have greatly facilitated this process by providing the experimental approaches of directed evolution or by enabling computer-assisted applications. Directed evolution mimics the natural selection process in a highly accelerated fashion at the expense of arduous laboratory work and economic resources. Theoretical methods provide predictions and represent an attractive complement to such experiments by waiving their inherent costs. Computational techniques can be used to engineer enzymatic reactivity, substrate specificity and ligand binding, access pathways and ligand transport, and global properties like protein stability, solubility, and flexibility. Theoretical approaches can also identify hotspots on the protein sequence for mutagenesis and predict suitable alternatives for selected positions with expected outcomes. This review covers the latest advances in computational methods for enzyme engineering and presents many successful case studies.

• Klíčová slova
• Biocatalyst, Catalytic efficiency, Computational enzyme design, Enzyme biotechnologies, Protein dynamics, Protein engineering, Software, Solubility, Stability,
• MeSH
• biokatalýza MeSH
• biotechnologie * MeSH
• enzymy genetika   metabolismus   MeSH
• mutageneze MeSH
• proteinové inženýrství MeSH
• řízená evoluce molekul * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• enzymy MeSH

The increasing use of silver nanoparticles (AgNPs) due to their well-known antimicrobial activity, has led to their accumulation in soil ecosystems. However, the impact of environmental realistic concentrations of AgNPs on the soil microbial community has been scarcely studied. In this work, we have assessed the impact of AgNPs, that mimic real concentrations in nature, on tropical soils cultivated with Coffea arabica under conventional and organic management systems. We evaluated the biomass, extracellular enzyme activities, and diversity of the soil microbial community, in a microcosm experiment as a function of time. After seven days of incubation, we found an increase in microbial biomass in an AgNPs-concentration-independent manner. In contrast, after 60-day-incubation, there was a decrease in Gram+ and actinobacterial biomass, in both soils and all AgNPs concentrations. Soil physico-chemical properties and enzyme activities were not affected overall by AgNPs. Regarding the microbial community composition, only some differences in the relative abundance at phylum and genus level in the fungal community were observed. Our results suggest that environmental concentrations of AgNPs affected microbial biomass but had little impact on microbial diversity and may have little effects on the soil biogeochemical cycles mediated by extracellular enzyme activities.

• Klíčová slova
• Ag nanoparticles, Biomass, Enzyme activities, Soil microbial community,
• MeSH
• Bacteria klasifikace   účinky léků   enzymologie   genetika   MeSH
• bakteriální geny MeSH
• beta-glukosidasa chemie   MeSH
• biomasa MeSH
• kovové nanočástice toxicita   MeSH
• kyselá fosfatasa chemie   MeSH
• látky znečišťující půdu toxicita   MeSH
• mikrobiota účinky léků   MeSH
• půdní mikrobiologie MeSH
• RNA ribozomální 16S MeSH
• stříbro toxicita   MeSH
• ureasa chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• beta-glukosidasa MeSH
• kyselá fosfatasa MeSH
• látky znečišťující půdu MeSH
• RNA ribozomální 16S MeSH
• stříbro MeSH
• ureasa MeSH

Nitric oxide (NO) is an endogenous vasodilator and inhaled NO is a promising therapeutic agent for the treatment of pulmonary hypertension. However, NO's mechanism of action is not completely understood. Previous studies have shown that NO increases intracellular levels of cyclic guanosine 3',5'-monophosphate (cGMP) and that leads to activation of calcium-gated potassium channels in vascular smooth muscle cells. Resulting cell membrane hyperpolarization causes vasorelaxation. The potassium channel activation by NO is inhibited by a blockade of cyclic nucleotide-dependent protein kinases, suggesting a key role of these enzymes in NO-induced vasodilation. To further examine this mechanism, we tested the hypothesis that pharmacological stimulation of the cGMP-dependent protein kinase will simulate the activating effect of NO on potassium channels. Indeed, we found that (Sp)-guanosine cyclic 3',5'-phosphorothioate (1 microM), a selective activator of the cGMP-dependent protein kinase, dramatically increased potassium currents measured by the whole-cell patch clamp technique in freshly dispersed pulmonary artery smooth muscle cells. These currents were inhibited by an inhibitor of calcium-gated potassium channels, charybdotoxin. Our results support the hypothesis that the effect of NO on potassium channels is mediated by the cGMP-dependent protein kinase.

• MeSH
• gating iontového kanálu účinky léků   MeSH
• guanosinmonofosfát cyklický farmakologie   MeSH
• krysa rodu Rattus MeSH
• membránové potenciály MeSH
• metoda terčíkového zámku MeSH
• oxid dusnatý farmakologie   MeSH
• potkani Sprague-Dawley MeSH
• proteinkinasy závislé na cyklickém GMP účinky léků   metabolismus   MeSH
• svaly hladké cévní účinky léků   metabolismus   MeSH
• vápníkové kanály účinky léků   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH
• Research Support, U.S. Gov't, P.H.S. MeSH
• Názvy látek
• guanosinmonofosfát cyklický MeSH
• oxid dusnatý MeSH
• proteinkinasy závislé na cyklickém GMP MeSH
• vápníkové kanály MeSH

Nanozymes (NZs) are nanomaterials that mimic enzyme-like catalytic activity. They have attracted substantial attention due to their inherent physicochemical properties for use as promising alternatives to natural enzymes (NEs) in a variety of research fields. Particularly, in biosensing and bioassays, NZs have opened a new horizon to eliminate the intrinsic limitations of NEs, including their denaturation at extreme pH values and temperatures, poor reusability and recyclability, and high production costs. Moreover, the catalytic activity of NZs can be modulated in the preparation step by following an appropriate synthesis strategy. This review aims to gain insight into the potential substitution of NEs by NZs in biosensing and bioassays while considering both the pros and cons.

• Klíčová slova
• Bioassay, Biosensing, Nanozymes, Natural enzymes,
• MeSH
• biosenzitivní techniky * MeSH
• biotest MeSH
• enzymy MeSH
• katalýza MeSH
• nanostruktury * MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• enzymy MeSH