• Klíčová slova
• ekonomika, obchod, statistika,

• NLK Obory
• ekonomie, ekonomika, ekonomika zdravotnictví
• ekonomie, ekonomika, ekonomika zdravotnictví

The fast and efficient detection of foodborne pathogens is a societal priority, given the large number of food-poisoning outbreaks, and a scientific and technological challenge, given the need to detect as little as 1 viable cell in 25 gr of food. Here, we present the first approach that achieves the above goal, thanks to the use of a micro/nano-technology and the detection capability of acoustic wave sensors. Starting from 1 Salmonella cell in 25 ml of milk, we employ immuno-magnetic beads to capture cells after only 3 h of pre-enrichment and subsequently demonstrate efficient DNA amplification using the Loop Mediated Isothermal Amplification method (LAMP) and acoustic detection in an integrated platform, within an additional ½ h. The demonstrated 4 h sample-to-analysis time comes as a huge improvement to the current need of few days to obtain the same result. In addition, the work presents the first reported Lab-on-Chip platform that comprises an acoustic device as the sensing element, exhibiting impressive analytical features, namely, an acoustic limit of detection of 2 cells/μl or 3 aM of the DNA target and ability to detect in a label-free manner dsDNA amplicons in impure samples. The use of food samples together with the incorporation of the necessary pre-enrichment step and ability for multiple analysis with an internal control, make the proposed methodology highly relevant to real-world applications. Moreover, the work suggests that acoustic wave devices can be used as an attractive alternative to electrochemical sensors in integrated platforms for applications in food safety and the point-of-care diagnostics.

• MeSH
• akustika přístrojové vybavení   MeSH
• analýza potravin přístrojové vybavení   MeSH
• biosenzitivní techniky přístrojové vybavení   MeSH
• design vybavení MeSH
• DNA bakterií analýza   genetika   MeSH
• kontaminace potravin analýza   MeSH
• laboratoř na čipu MeSH
• lidé MeSH
• limita detekce MeSH
• mléko mikrobiologie   MeSH
• nemoci přenášené potravou mikrobiologie   MeSH
• potravinářská mikrobiologie MeSH
• Salmonella genetika   izolace a purifikace   MeSH
• salmonelóza mikrobiologie   MeSH
• zvířata MeSH
• zvuk MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• hodnotící studie MeSH

For the pretreatment of wood, charcoal and collagen from bone micro samples using the Acid-Base-Acid (ABA) method, we have assembled an automated computer-controlled unit in our laboratory CRL. The sample is placed in a glass single-necked cuvette. The machine consists of prepared solutions which are guided through capillaries, switching valve and peristaltic pump into the cuvette with the sample according to the currently selected program. The automat can be used for the pretreatment of charcoal, wood and also collagen from bones.

• MeSH
• alkálie chemie   MeSH
• dřevěné a živočišné uhlí chemie   MeSH
• dřevo chemie   MeSH
• kolagen chemie   MeSH
• kosti a kostní tkáň chemie   MeSH
• kyseliny chemie   MeSH
• laboratorní automatizace metody   MeSH
• lidé MeSH
• radioaktivní datování metody   MeSH
• radioizotopy uhlíku analýza   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

This contribution describes properties and utilization of free liquid membranes (FLMs) in micro-electromembrane extraction (μ-EME) of analytes from samples with complex matrices. An FLM was formed as a plug of a selected organic solvent, 1-ethyl-2-nitrobenezene (ENB) or 2-nitrophenyloctyl ether, in a narrow bore polymeric tubing and was sandwiched between a plug of aqueous donor and aqueous acceptor solution. The FLM acted as a phase interface that enabled selective transfer of analytes from donor into acceptor solution. Acceptor solution after μ-EME was analysed by capillary electrophoresis (CE). Fundamental characteristics of FLMs were depicted and discussed by presenting experimental data on their performance for various basic operational parameters, such as composition and volume of donor/acceptor solution, applied extraction voltage, thickness of FLM and extraction time. Positively charged basic drugs (nortriptyline, haloperidol and loperamide) and their solutions in water, urine and blood serum served as model samples. It was shown that FLMs may offer fast, efficient and selective pretreatment of crude biological samples providing that basic operational parameters of μ-EME are set properly. At optimised conditions, basic drugs in 1.5μL of a biological sample were transferred across 1.5μL of FLM (ENB) into 1.5μL of acceptor solution in about 5min at an extraction voltage of 100V. Repeatability values of μ-EMEs and CE-UV analyses of the three basic drugs were better than 7.7% for peak areas, recoveries ranged between 19 and 52% and linear relationship was obtained for analytical signal vs. concentration in 1-50mgL(-1) range (r(2) better than 0.996). Limits of detection, defined as 3×S/N, were below 1mgL(-1) for all examined matrices.

• MeSH
• elektřina MeSH
• elektroforéza kapilární metody   MeSH
• léčivé přípravky krev   moč   MeSH
• lidé MeSH
• membrány umělé * MeSH
• nitrobenzeny chemie   MeSH
• rozpouštědla MeSH
• roztoky MeSH
• voda MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

A two-phase micro-electromembrane extraction (μ-EME) using a floating drop of an organic solvent was presented for rapid and efficient pretreatment of complex biological samples. The μ-EME system consisted of a glass vial containing aqueous sample (donor solution) and a small drop of a water-immiscible organic solvent (4-nitrocumene), which was floating on the surface of the aqueous solution in form of a free liquid membrane (FLM). The vial geometry and the optimized volume ratios of the donor and the FLM ensured a stable position of the FLM in the center of the vial during μ-EME, and one electrode of a d.c. power supply was inserted directly into the FLM while the other electrode was placed into the aqueous sample. The active surface area of the floating drop FLM contacting the sample was considerably larger in comparison to formerly reported μ-EME formats employing FLMs and resulted in a faster and a more efficient transfer of target analytes from the sample to the FLM. Four basic drugs (nortriptyline, papaverine, loperamide, and haloperidol) were selected as model analytes and were extracted from physiological solution, human urine, and dried blood spot samples. At the optimized μ-EME conditions (250 V, 15 min, 300 rpm, acidic donor) and the optimized ratio of the sample to the FLM volume (500:14 μL), extraction recoveries between 49 and 100% and enrichment factors up to 35.7 were achieved. Quantitative analyses of the basic drugs in the resulting FLMs (diluted with methanol) were performed by capillary electrophoresis with ultraviolet detection and demonstrated excellent repeatability (RSD ≤ 4.9%) and linearity (r2 ≥ 0.9997), and low limits of detection (5-28 ng/mL) of the method.

• Publikační typ
• časopisecké články MeSH

Micro-electromembrane extraction (μ-EME) was presented for the selective extraction of four main β-lactam antibiotics (penicillin, phenoxypenicillin, ampicillin, and amoxicillin) from complex samples. A volatile solvent (ethyl acetate or chloroform) was sandwiched between a plug of the complex sample and another plug of an aqueous acceptor solution in a transparent polymeric tube and formed the so-called free liquid membrane (FLM). The use of the FLM eliminated the evaporation of the solvent and enabled the μ-EME of the antibiotics, which was carried out by the application of DC voltage to the terminal aqueous solutions. The drugs in the complex sample were selectively transferred through the FLM to the acceptor solution, which was directly used for their determination by micellar electrokinetic chromatography with ultraviolet detection (MEKC-UV). The μ-EME was characterized by sub-μA electric currents, high elimination of matrix components, high stability of operational solutions, and suitability for extracting undiluted complex samples. The μ-EME/MEKC-UV method yielded good analytical repeatability (RSDs of peak areas ≤5%), extraction recoveries (40-84%), accuracy (92-105%) and linearity over one and a half order of magnitude (R2 ≥ 0.9998), and was applied to the determination of the four β-lactam antibiotics in human serum and waste water at clinically and environmentally relevant concentration levels. Further improvement in the method sensitivity was achieved by changing the μ-EME tube geometry (conical shape) and increasing the complex sample volume (100 μL). The analytes were enriched by factors of 7.6-11.5, the limits of detection dropped down to less than 18 ng/mL, and the modified μ-EME/MEKC-UV method enabled the trace determination of β-lactam antibiotics in complex samples.

• MeSH
• antibakteriální látky MeSH
• beta-laktamy MeSH
• elektřina * MeSH
• lidé MeSH
• membrány umělé * MeSH
• rozpouštědla MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

Micro-electrodialysis (μED) and CE were combined for rapid pretreatment and subsequent determination of inorganic cations in biological samples. Combination of μED with CE greatly improved the analytical performance of the latter as the adsorption of high molecular weight compounds present in real samples on the inner capillary wall was eliminated. Fifty microliter of 80-fold diluted human body fluids such as plasma, serum and whole blood was used in the donor compartment of the μED system requiring less than 1 μL of the original body fluid per analysis. Inorganic cations that migrated through a cellulose acetate dialysis membrane with molecular weight cut-off value of 500 Da were collected in the acceptor solution and were then analyzed using CE-C⁴D. Baseline separation of inorganic cations was achieved in a BGE solution consisting of 12.5 mM maleic acid, 15 mM L-arginine and 3 mM 18-crown-6 at pH 5.5. Repeatability of the CE-C⁴D method was better than 0.5% and 2.5% for migration times and peak areas, respectively; limits of detection of all inorganic cations in the presence of 2 mM excess of Na(+) were around 1 μM and calibration curves were linear with correlation coefficients better than 0.998. Repeatability of the sample pretreatment procedure was calculated for six independent electrodialysis runs of artificial and real samples and was better than 11.8%. Recovery values between 96.3 and 110% were achieved for optimized electrodialysis conditions of standard solutions and real samples; lifetime of the dialysis membranes for pretreatment of real samples was estimated to 100 runs.

• MeSH
• elektrická vodivost MeSH
• elektroforéza kapilární metody   MeSH
• elektrolyty chemie   MeSH
• kationty analýza   krev   MeSH
• krev metabolismus   MeSH
• krevní plazma metabolismus   MeSH
• lidé MeSH
• mikrodialýza přístrojové vybavení   MeSH
• reprodukovatelnost výsledků MeSH
• roztoky chemie   MeSH
• sérum metabolismus   MeSH
• tělesné tekutiny chemie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

A simple sample injection procedure compatible with commercial capillary electrophoresis (CE) instrumentation was developed, which enables handling sample volumes as little as 250nL for analytical applications where sample volume availability is of concern. Single-use micro-sampling inserts were prepared by thermal modification of polypropylene micropipette tips and the inserts were accommodated in standard CE vials in CE autosampler carousel. To ensure direct contact of separation capillary injection end with sample solution and to avoid possible damage to the capillary, a soft compression spring was placed at the bottom of the vial underneath the micro-sampling insert. Injections from sub-μL samples were carried out in conventional as well as in short-end injection mode, were compatible with standard i.d./o.d. (25-100μm/365μm) fused silica capillaries and with various background electrolyte solutions and detection modes. Excellent repeatability of replicate injections from 250nL to 3μL was achieved based on RSD values of quantitative analytical measures (peak heights ≤2.4% and peak areas ≤3.7%) for CE-UV-vis, CE-ESI-MS and CE-contactless conductivity detection of model basic drugs. The achieved RSD values were comparable with those for replicate injections of the drugs from standard CE vials. The reported concept of injections from micro-sampling inserts was further demonstrated useful in evaluation of micro-electromembrane extraction (μ-EME) of model basic drugs. Sub-μL volumes of operational solutions resulted in reduced lengths of μ-EME phases and improved extraction recoveries (66-91%) were achieved.

• MeSH
• elektroforéza kapilární přístrojové vybavení   metody   MeSH
• elektrolyty chemie   MeSH
• hmotnostní spektrometrie MeSH
• nortriptylin analýza   izolace a purifikace   MeSH
• papaverin analýza   MeSH
• roztoky chemie   MeSH
• spektrofotometrie ultrafialová MeSH
• Publikační typ
• časopisecké články MeSH

OBJECTIVE: Molecular pathogenesis of Down syndrome (DS) is still incompletely understood. Epigenetic mechanisms, including miRNAs gene expression regulation, belong to potential influencing factors. The aims of this study were to compare miRNAs expressions in placentas with normal and trisomic karyotype and to associate differentially expressed miRNAs with concrete biological pathways. METHODS: A total of 80 CVS samples - 41 with trisomy 21 and 39 with normal karyotype - were included in our study. Results obtained in the pilot study using real-time PCR technology and TaqMan Human miRNA Array Cards were subsequently validated on different samples using individual TaqMan miRNA Assays. RESULTS: Seven miRNAs were verified as upregulated in DS placentas (miR-99a, miR-542-5p, miR-10b, miR-125b, miR-615, let-7c and miR-654); three of these miRNAs are located on chromosome 21 (miR-99a, miR-125b and let-7c). Many essential biological processes, transcriptional regulation or apoptosis, were identified as being potentially influenced by altered miRNA levels. Moreover, miRNAs overexpressed in DS placenta apparently regulate genes involved in placenta development (GJA1, CDH11, EGF, ERVW-1, ERVFRD-1, LEP or INHA). CONCLUSION: These findings suggest the possible participation of miRNAs in Down syndrome impaired placentation and connected pregnancy pathologies. © 2016 John Wiley & Sons, Ltd.

• MeSH
• dospělí MeSH
• Downův syndrom genetika   metabolismus   MeSH
• epidermální růstový faktor genetika   MeSH
• epigeneze genetická MeSH
• genové produkty env genetika   MeSH
• inhibiny genetika   MeSH
• kadheriny genetika   MeSH
• konexin 43 genetika   MeSH
• kvantitativní polymerázová řetězová reakce MeSH
• leptin genetika   MeSH
• lidé MeSH
• mikro RNA genetika   metabolismus   MeSH
• odběr choriových klků MeSH
• pilotní projekty MeSH
• placenta metabolismus   MeSH
• placentace genetika   MeSH
• studie případů a kontrol MeSH
• těhotenské proteiny genetika   MeSH
• těhotenství MeSH
• transkriptom MeSH
• upregulace MeSH
• vývojová regulace genové exprese genetika   MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• těhotenství MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

Soil micro-organisms drive the global carbon and nutrient cycles that underlie essential ecosystem functions. Yet, we are only beginning to grasp the drivers of terrestrial microbial diversity and biogeography, which presents a substantial barrier to understanding community dynamics and ecosystem functioning. This is especially true for soil protists, which despite their functional significance have received comparatively less interest than their bacterial counterparts. Here, we investigate the diversification of Pinnularia borealis, a rare biosphere soil diatom species complex, using a global sampling of >800 strains. We document unprecedented high levels of species-diversity, reflecting a global radiation since the Eocene/Oligocene global cooling. Our analyses suggest diversification was largely driven by colonization of novel geographic areas and subsequent evolution in isolation. These results illuminate our understanding of how protist diversity, biogeographical patterns, and members of the rare biosphere are generated, and suggest allopatric speciation to be a powerful mechanism for diversification of micro-organisms.

• MeSH
• Bacteria klasifikace   genetika   růst a vývoj   MeSH
• biodiverzita * MeSH
• druhová specificita MeSH
• ekosystém * MeSH
• fylogeneze MeSH
• molekulární evoluce MeSH
• půdní mikrobiologie * MeSH
• rozsivky klasifikace   genetika   růst a vývoj   MeSH
• sekvenční analýza DNA MeSH
• zeměpis MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH