In an effort to establish reliable thermodynamic data for amino acids, heat capacity and phase behavior are reported for L-cysteine (CAS RN: 52-90-4), L-serine (CAS RN: 56-45-1), L-threonine (CAS RN: 72-19-5), L-lysine (CAS RN: 56-87-1), and L-methionine (CAS RN: 63-68-3). Prior to heat capacity measurements, initial crystal structures were identified by X-ray powder diffraction, followed by a thorough investigation of the polymorphic behavior using differential scanning calorimetry in the temperature range from 183 K to the decomposition temperature determined by thermogravimetric analysis. Crystal heat capacities of all five amino acids were measured by Tian-Calvet calorimetry in the temperature interval (262-358) K and by power compensation DSC in the temperature interval from 215 K to over 420 K. Experimental values of this work were compared and combined with the literature data obtained with adiabatic calorimetry. Low-temperature heat capacities of L-threonine and L-lysine, for which no or limited literature data was available, were measured using the relaxation (heat pulse) calorimetry. As a result, reference heat capacities and thermodynamic functions for the crystalline phase from near 0 K to over 420 K were developed.

• Klíčová slova
• L-cysteine, L-lysine, L-methionine, L-serine, L-threonine, crystalline phase, heat capacity,
• MeSH
• cystein chemie   MeSH
• lysin * MeSH
• methionin MeSH
• serin MeSH
• threonin MeSH
• vysoká teplota * MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• cystein MeSH
• lysin * MeSH
• methionin MeSH
• serin MeSH
• threonin MeSH

Using mutagenesis with N-methyl-N'-nitro-N-nitrosoguanidine, a number of homoserine auxotrophs have been isolated from a glutamate-producing Arthrobacter globiformis excreting L-lysine in good amounts. For further improvement, mutants resistant to the lysine analog S-(2-aminoethyl)-L-cysteine have been isolated from homoserine auxotrophs. For the three potent mutants tested, White's medium was found to be the best. Glucose, ammonium nitrate and biotin were found to be optimum at 280 mmol/L, 40 mmol/L and 22 nmol/L, respectively. With optimal glucose, ammonium nitrate and biotin, the strain AECrVI yielded 36 g lysine per L in flask culture.

• MeSH
• antibiotická rezistence genetika   MeSH
• Arthrobacter účinky léků   genetika   metabolismus   MeSH
• biotin farmakologie   MeSH
• cystein analogy a deriváty   farmakologie   MeSH
• druhová specificita MeSH
• dusík metabolismus   MeSH
• glukosa metabolismus   MeSH
• kultivační média MeSH
• lysin biosyntéza   MeSH
• methylnitronitrosoguanidin MeSH
• mutace MeSH
• mutageneze MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• biotin MeSH
• cystein MeSH
• dusík MeSH
• glukosa MeSH
• kultivační média MeSH
• lysin MeSH
• methylnitronitrosoguanidin MeSH
• S-2-aminoethyl cysteine MeSH Prohlížeč

Intensive agricultural practices impact the health and nutrition of pollinators like honey bees (Apis mellifera). Rapeseed (Brassica napus L.) is widely cultivated, providing diverse nutrients and phytochemicals, including S-methyl-L-cysteine sulfoxide (SMCSO). While the nutritional impact of rapeseed on bees is known, SMCSO's effects remain unexplored. We examined SMCSO and its related metabolites-3-methylthiolactic acid sulfoxide and N-acetyl-S-methyl-L-cysteine sulfoxide-analysing their seasonal fluctuations, colony variations and distribution in body parts. Our findings showed that these compounds in bee gut vary among colonies, possibly due to the dietary preferences, and are highly concentrated in bodies during the summer. They are distributed differently within bee bodies, with higher concentrations in the abdomens of foragers compared with nurses. Administration of SMCSO in a laboratory setting showed no immediate toxic effects but significantly boosted bees' antioxidant capacity. Long-term administration decreased bee body weight, particularly in the thorax and head, and altered amino acid metabolism. SMCSO is found in the nectar and pollen of rapeseed flowers and highly accumulates in rapeseed honey compared with other types of honey. This study reveals the dual impact of SMCSO on bee health, providing a basis for further ecological and physiological research to enhance bee health and colony sustainability.

• Klíčová slova
• Apis mellifera, Brassicaceae, S-methyl-L-cysteine sulfoxide, phytochemical, rapeseed, toxicity,
• MeSH
• antioxidancia farmakologie   MeSH
• Brassica napus metabolismus   MeSH
• Brassicaceae chemie   MeSH
• cystein * analogy a deriváty   metabolismus   MeSH
• fytonutrienty farmakologie   MeSH
• med analýza   MeSH
• opylení MeSH
• pyl chemie   MeSH
• roční období MeSH
• včely účinky léků   fyziologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antioxidancia MeSH
• cystein * MeSH
• fytonutrienty MeSH

Garlic is a valuable source of healthy compounds, including secondary metabolites rich in sulphur such as cysteine sulphoxides (CSOs). Here, we present new qRT-PCR assays analysing the transcription of two genes encoding key enzymes in CSO biosynthetic pathways (cysteine synthase and alliinase) in developing garlic. We also identified a set of genes (ACT I, GAPDH, and TUB) to use as transcription normalisation controls. We showed that the (normalised) transcription of both enzymes was highest during sprouting and decreased significantly in fully developed leaves, which are the major CSO-producing organs. Transcriptional activity further declined at the end of the growing season. Different cultivars show similar sulphur metabolism gene expression when European garlics were compared to Chinese and American genotypes. The qRT-PCR assays presented are also suitable for investigating the effects of agricultural practices on CSO formation in garlic to satisfy consumer demands.

• Klíčová slova
• Alliinase, Allium sativum L., Cysteine synthase, Garlic, Housekeeping genes, Normalisation, Transcription profiling,
• MeSH
• česnek enzymologie   genetika   růst a vývoj   MeSH
• cystein metabolismus   MeSH
• cysteinsynthasa genetika   MeSH
• listy rostlin enzymologie   genetika   MeSH
• lyasy štěpící vazby C-S genetika   MeSH
• polymerázová řetězová reakce s reverzní transkripcí MeSH
• regulace genové exprese u rostlin MeSH
• rostlinné proteiny genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• alliin lyase MeSH Prohlížeč
• cystein MeSH
• cysteinsynthasa MeSH
• lyasy štěpící vazby C-S MeSH
• rostlinné proteiny MeSH

Two mercapturic acids, i.e., N-acetyl-S-(1-cyano-2-hydroxyethyl)-L-cysteine (CHEMA) and N-acetyl-S-(2-hydroxyethyl)-L-cysteine (HEMA), were isolated from the urine of rats dosed with four successive doses of oxiranecarbonitrile (glycidonitrile, GN), 5 mg/kg, a reactive metabolic intermediate of acrylonitrile (AN). GC-MS analysis of methylated urine extracts from both AN- and GN-dosed rats showed another mercapturate which was identified as N-acetyl-S-(1-cyanoethenyl)-L-cysteine (1-CEMA) methyl ester using an authentic reference sample. The mass spectrum of this compound was very similar to that of a methylated metabolite of AN tentatively identified by Langvardt et al. (1980) as N-acetyl-3-carboxy-5-cyanothiazane (ACCT). In contrast, no ACCT was found in rats dosed with either GN or AN. Hence, there is no evidence for the formation of ACCT or its isomers in rats dosed with AN or GN. The methyl ester of 1-CEMA is formed artificially by dehydration of CHEMA methyl ester in the injector of the gas chromatograph.

• MeSH
• acetylcystein analogy a deriváty   moč   MeSH
• akrylonitril metabolismus   MeSH
• biotransformace MeSH
• ethylenoxid analogy a deriváty   metabolismus   MeSH
• inbrední kmeny potkanů MeSH
• krysa rodu Rattus MeSH
• nitrily metabolismus   MeSH
• stereoizomerie MeSH
• thiaziny metabolismus   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• 2-cyanoethylene oxide MeSH Prohlížeč
• acetylcystein MeSH
• akrylonitril MeSH
• ethylenoxid MeSH
• N-acetyl-3-carboxy-5-cyanotetrahydro-1,4-2H-thiazine MeSH Prohlížeč
• N-acetyl-S-(1-cyano-2-hydroxyethyl)cysteine MeSH Prohlížeč
• N-acetyl-S-(2-hydroxyethyl)cysteine MeSH Prohlížeč
• nitrily MeSH
• thiaziny MeSH

Cysteine dioxygenase (CDO) is involved in regulation of intracellular cysteine levels by catabolising the cysteine to sulphite and sulphate. In keratinolytic fungi, sulphite is actively excreted to reduce disulphide bridges in keratin before its enzymatic degradation. The pathogenicity role of CDO was confirmed in cysteine-hypersensitive and growth-defective ΔCdo mutant of Arthroderma benhamiae on hair and nails. We analysed the CDO expression regulation in T. mentagrophytes (anamorph of A. benhamiae) mycelia by determining the Cdo mRNA and CDO protein levels and by analysing the proportion of two molecular forms of CDO in response to l-cystine exposure. Cdo mRNA levels in mycelia lysates were detected by reverse-transcription real-time polymerase chain reaction and CDO protein by western blot using mouse CDO-specific hyperimmune serum. The Cdo mRNA level increased gradually 2.5-4.5 h after exposure of the mycelium to l-cystine. The CDO protein, detected as two bands of different mobility, appeared earlier in comparison to mRNA (1 h) and culminated after 24 h. More mobile form prevailed after 4.5 h. The comparison of the dynamics in the Cdo mRNA and CDO protein levels indicates that T. mentagrophytes responds to l-cystine by increased transcription and apparently decreased degradation of the CDO and by changing towards higher mobility molecular form, similar to previous reports describing mammalian analogue.

• Klíčová slova
• Cysteine dioxygenase, dermatophytes, keratinolysis, vaccination,
• MeSH
• cysteindioxygenasa genetika   metabolismus   MeSH
• cystin metabolismus   MeSH
• fungální proteiny genetika   metabolismus   MeSH
• lidé MeSH
• mycelium enzymologie   genetika   růst a vývoj   metabolismus   MeSH
• myši inbrední BALB C MeSH
• myši MeSH
• regulace genové exprese enzymů * MeSH
• tinea mikrobiologie   MeSH
• Trichophyton enzymologie   genetika   růst a vývoj   fyziologie   MeSH
• upregulace MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• cysteindioxygenasa MeSH
• cystin MeSH
• fungální proteiny MeSH

We report a novel impedimetric sensor based on a graphite electrode impregnated with polyethylene and paraffin under vacuum (IGE) modified with electrochemically deposited gold and a self-assembled monolayer of N-acetyl-L-cysteine (NAC/Au/IGE) for selective and sensitive determination of extracellular hydroxyl radicals (OH•) generated by living cells. The application of a sulphur-containing molecule oxidized by OH• predicts the high selectivity of the sensor, and the utilization of the non-faradaic impedance spectroscopy for recording an analytical response makes it possible to achieve superior sensitivity with a detection limit of 0.01 nM and a linear dynamic range of 0.08-8 nM. Meanwhile, NAC/Au/IGE demonstrated a strong potential of detecting OH• generated by biological objects via successful determination of extracellular hydroxyl radicals generated by normal fibroblast cells and prostate carcinoma cells.

• Klíčová slova
• Cell cultures, Hydroxyl radical, Impedimetric sensor, N-Acetyl-L-cysteine, Oxidative stress,
• MeSH
• acetylcystein MeSH
• biosenzitivní techniky * metody   MeSH
• buněčné kultury MeSH
• elektrochemické techniky metody   MeSH
• elektrody MeSH
• hydroxylový radikál * MeSH
• imunoglobulin E MeSH
• limita detekce MeSH
• zlato chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• acetylcystein MeSH
• hydroxylový radikál * MeSH
• imunoglobulin E MeSH
• zlato MeSH

The L-cysteine-functionalized silica (SG-Cys-Na+) matrix was effectively loaded with silver (I) ions using the batch sorption technique. Optimal Ag(I) loading into SG-Cys-Na+ reached 98% at pHi = 6, 80 rpm, 1 mg L-1, and a temperature of 55 °C. The Langmuir isotherm was found to be suitable for Ag(I) binding onto SG-Cys-Na+ active sites, forming a homogeneous monolayer (R2 = 0.999), as confirmed by FTIR spectroscopy. XRD analysis indicated matrix stability and the absence of Ag2O and Ag(0) phases, observed from diffraction peaks. The pseudo-second-order model (R2 > 0.999) suggested chemisorption-controlled adsorption, involving chemical bonding between silver ions and SG-Cys-Na+ surface. Thermodynamic parameters were calculated, indicating higher initial concentrations leading to increased equilibrium constants, negative ΔG values, positive ΔS values, and negative ΔH. This study aimed to explore silver ion saturation on silica surfaces and the underlying association mechanisms. The capability to capture and load silver (I) ions onto functionalized silica gel materials holds promise for environmental and water purification applications.

• Klíčová slova
• L-cysteine, Langmuir isotherm, silica gel, silver (I) Ion, thermodynamic parameters,
• Publikační typ
• časopisecké články MeSH

The composition of garlic (Allium sativum L.) may vary among cultivars and, moreover, change over time, thereby affecting both biological activity and flavour. Thus, it is important to identify the trends in the content of bioactive compounds in garlic, by reliable analytical methods. This study was focused on the key sulfur-containing compounds, S-alk(en)yl-L-cysteine sulfoxides (alliin, isoalliin, methiin, propiin), which were quantified by a fast liquid chromatography - tandem mass spectrometry (LC-MS/MS) method. Several garlic cultivars were monitored repeatedly within seven months: one month before harvest maturity; at harvest maturity; and after two and six months of storage. The results showed not only a high variability among individual cultivars, but also among samples of the same cultivar grown at different localities. During storage, a significant increase in isoalliin content (up to 54-fold after six months) occurred. Nevertheless, none of the cultivars showed significantly different properties compared to others, suggesting that many other factors affect garlic composition.

• Klíčová slova
• Alliin, Allium sativum L., Cultivar, Locality, Storage,
• MeSH
• česnek * MeSH
• chromatografie kapalinová MeSH
• cystein MeSH
• sulfoxidy MeSH
• tandemová hmotnostní spektrometrie MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• cystein MeSH
• sulfoxidy MeSH

In the food industry, the increasing antimicrobial resistance of food-borne pathogens to conventional sanitizers poses the risk of food contamination and a decrease in product quality and safety. Therefore, we explored alternative antimicrobials N-Acetyl-l-cysteine (NAC), rhamnolipids (RLs), and usnic acid (UA) as a novel approach to prevent biofilm formation and reduce existing biofilms formed by important food-borne pathogens (three strains of Salmonella enterica and two strains of Escherichia coli, Listeria monocytogenes, Staphylococcus aureus). Their effectiveness was evaluated by determining minimum inhibitory concentrations needed for inhibition of bacterial growth, biofilm formation, metabolic activity, and biofilm reduction. Transmission electron microscopy and confocal scanning laser microscopy followed by image analysis were used to visualize and quantify the impact of tested substances on both planktonic and biofilm-associated cells. The in vitro cytotoxicity of the substances was determined as a half-maximal inhibitory concentration in five different cell lines. The results indicate relatively low cytotoxic effects of NAC in comparison to RLs and UA. In addition, NAC inhibited bacterial growth for all strains, while RLs showed overall lower inhibition and UA inhibited only the growth of Gram-positive bacteria. Even though tested substances did not remove the biofilms, NAC represents a promising tool in biofilm prevention.

• Klíčová slova
• N-Acetyl-l-cysteine, acute cytotoxicity, antimicrobial efficacy, bacterial growth, biofilm, food-borne pathogens, minimum inhibitory concentrations, rhamnolipids, usnic acid,
• MeSH
• acetylcystein farmakologie   MeSH
• antibakteriální látky farmakologie   MeSH
• antiinfekční látky farmakologie   MeSH
• benzofurany farmakologie   MeSH
• biofilmy účinky léků   MeSH
• buněčné linie MeSH
• Escherichia coli účinky léků   MeSH
• glykolipidy farmakologie   MeSH
• kontaminace potravin prevence a kontrola   MeSH
• lidé MeSH
• Listeria monocytogenes účinky léků   MeSH
• mikrobiální testy citlivosti MeSH
• nemoci přenášené potravou farmakoterapie   mikrobiologie   MeSH
• potravinářská mikrobiologie metody   MeSH
• Salmonella enterica účinky léků   MeSH
• Staphylococcus aureus účinky léků   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• acetylcystein MeSH
• antibakteriální látky MeSH
• antiinfekční látky MeSH
• benzofurany MeSH
• glykolipidy MeSH
• rhamnolipid MeSH Prohlížeč
• usnic acid MeSH Prohlížeč