EU Regulation 396/2005: Pesticide Residue Testing and the Critical Role of QuEChERS Evaporation in Food Safety

<div><div>Researchers led by <a target="_blank" rel="noopener noreferrer" href="https://kudova.group.uochb.cz/en">Eva Kudová</a> from IOCB Prague and Jitka Viktorová from UCT Prague have identified new androstane-based steroid derivatives that can significantly improve the effectiveness of existing antibiotics against multidrug-resistant Staphylococcus aureus.</div></div><div>The team screened dozens of natural steroidal hormones and synthetic derivatives to see whether they could block bacterial efflux pumps – mechanisms that bacteria use to eject antibiotics and survive treatment. Two compounds emerged as particularly promising: they inhibited efflux pumps and lowered the effective doses of antibiotics such as ciprofloxacin and erythromycin.Further analysis showed that one of the compounds also suppressed genes linked to bacterial virulence. Another key finding is that the most active molecules are non-toxic to human immune cells and showed no detectable endocrine activity, suggesting a favorable safety profile.These findings support the idea that rationally designed steroid-based molecules could act as antibiotic adjuvants, helping existing drugs overcome bacterial resistance.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/IOCB_Prague_Steroidal_hormones_and_neurosteroids_novel_therapeutic_strategies_in_bacterial_infections_8e5d2a7b48.jpg" alt="IOCB Prague: Steroidal hormones and neurosteroids – novel therapeutic strategies in bacterial infections" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_IOCB_Prague_Steroidal_hormones_and_neurosteroids_novel_therapeutic_strategies_in_bacterial_infections_8e5d2a7b48.jpg 222w," sizes="100vw" width="1258" height="886"><blockquote><h4>Original Article</h4><h4><a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0223523426001613?via%3Dihub">Steroidal hormones and neurosteroids - novel therapeutic strategies in bacterial infections: Design, synthesis, and biological evaluation</a></h4>Daniela Brdová, Bára Křížkovská, Jan Špaček, Zdeněk Míchal, Eva Jablonská, Ondřej Strnad, Hana Chodounská, Eszter Szánti-Pintér, Marina Morozovová, Václav Hanžl, Jan Tkadlec, Martijn Riool, Jan Lipov, Jitka Viktorová, Eva Kudová&nbsp;Eur. J. Med. Chem., 2026, 308, 118716<a target="_blank" rel="noopener noreferrer" href="https://doi.org/10.1016/j.ejmech.2026.118716">https://doi.org/10.1016/j.ejmech.2026.118716</a><h6>licensed under <a target="_blank" rel="noopener noreferrer" href="https://creativecommons.org/licenses/by/4.0/">CC-BY 4.0</a></h6></blockquote><h4>Abstract</h4>The global rise of antibiotic resistance necessitates novel therapeutic strategies for infectious diseases. Inhibition of bacterial efflux pumps, which contribute to multidrug resistance, represents a promising approach to restore or even increase the efficacy of existing antibiotics. Using fluorescence-based ethidium bromide accumulation, broth microdilution, and checkerboard assays, we evaluated 26 endogenous steroidal hormones and neurosteroids, along with 30 synthetic derivatives, for their ability to enhance antibiotic susceptibility in multidrug-resistant Staphylococcus aureus. Structure-activity relationship analysis identified compounds 13 and 16 as lead candidates, exhibiting strong efflux pump inhibition and marked reductions in the minimum inhibitory concentrations of ciprofloxacin and erythromycin. Both compounds showed additive effects in checkerboard assays. Modifications at C-3 (polar substitution) and C-17 (3α,5β-stereochemistry and nonpolar substitution) were essential for potent efflux inhibition and sensitization, although these modifications were not additive when combined. Transcriptome analysis further revealed that compound 13 significantly downregulated S. aureus virulence-associated genes when administered alone or in combination with antibiotics. Cytotoxicity assessment in human peripheral blood mononuclear cells and receptor transactivation assays for estrogen, androgen, and progesterone receptors indicated that the most active derivatives were non-toxic and lacked detectable endocrine activity, suggesting a favorable safety profile. Overall, these findings support the concept that rationally designed andostane-based steroidal scaffolds can function as competitive bacterial efflux pump inhibitors and serve as potential antibiotic adjuvants to mitigate efflux-mediated resistance.<h4>Instrumentation</h4><h5>Structural characterization</h5><ul><li>AVANCE III 400 MHz NMR spectrometer (Bruker)</li><li><a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/library?mainauthorItems=3&amp;search=LTQ+Orbitrap+XL">LTQ Orbitrap XL HRMS</a> (Thermo Fisher Scientific, ESI)</li></ul></div>

Steroidal hormones and neurosteroids – novel therapeutic strategies in bacterial infections

Metformin is currently the first-line oral drug of choice for the treatment of type 2 diabetes. It reduces glucose production in the liver, improves tissue sensitivity to insulin, and does not cause weight gain or hypoglycemia, which sets it apart from some other antidiabetic drugs. Moreover, its long-term beneficial effects on the risk of cardiovascular complications and mortality in people with type 2 diabetes have been well established. Researchers from the Institute of Physiology CAS (IPHYS) have identified a new group of blood metabolites that could help physicians objectively monitor whether patients with type 2 diabetes are taking their metformin as prescribed.<h4>New biomarkers for metformin use</h4>A team led by Tomáš Čajka from the Laboratory of Translational Metabolism at IPHYS analyzed plasma samples from 637 patients with type 2 diabetes treated with metformin and 143 non-diabetic controls using advanced metabolomics and lipidomics. Among 614 detected metabolites, they identified five from the group of N-lactoyl-amino acids (e.g. N‑lactoyl-phenylalanine), which had previously been seen as unknown signals due to missing reference spectra in databases. The levels of these metabolites in the blood closely reflected the plasma concentrations of metformin. In patients with the highest metformin exposure, the concentrations of these metabolites were up to 7.2 times higher than in controls.<h4>A sensitive “fingerprint” of the drug’s effect</h4>N-Lactoyl-amino acids are formed in cells by combining lactate and amino acids, thus reflecting the metformin-induced changes in cellular energy metabolism. “Importantly, even though they occur in plasma only at nanomolar concentrations, they reliably distinguish patients who take metformin regularly from those who take it irregularly or not at all,” emphasizes T. Čajka.<h4>Metabolomics in practice and international collaboration</h4>The study also provides a detailed description of broader metabolic changes in type 2 diabetes, including increases in lactate, organic acids, and branched-chain amino acids, as well as extensive remodelling of the lipid profile. In addition to T. Čajka’s team, collaborators from the Institute for Clinical and Experimental Medicine in Prague and the West Coast Metabolomics Center (University of California, Davis) also participated in the study.The results demonstrate that advanced metabolomics approaches developed at IPHYS within the CarDia project can find highly practical applications both in clinical studies and in personalized monitoring of treatment in patients with diabetes.<blockquote><h4>The original article</h4><h4><a target="_blank" rel="noopener noreferrer" href="https://ascpt.onlinelibrary.wiley.com/doi/10.1002/cpt.70205">Untargeted Metabolomics Identifies N-Lactoyl-Amino Acids as Dose-Responsive Plasma Biomarkers of Metformin Adherence in Type 2 Diabetes</a></h4>Tomas Cajka, Jiri Hricko, Lucie Rudl Kulhava, Michaela Paucova, Michaela Novakova, Veronika Hola, Stanislava Rakusanova, Oliver Fiehn, Vojtech Skop, Ivana Lankova, Iva Miskova, Terezie Pelikanova, Martin HaluzikClin Pharmacol Ther, 119: 1057-1069<a target="_blank" rel="noopener noreferrer" href="https://doi.org/10.1002/cpt.70205">https://doi.org/10.1002/cpt.70205</a><h6>licensed under <a target="_blank" rel="noopener noreferrer" href="https://creativecommons.org/licenses/by/4.0/">CC-BY 4.0</a></h6></blockquote><h4>Abstract</h4>Metformin is the most widely prescribed antidiabetic drug, yet adherence remains difficult to objectively assess. Using untargeted metabolomics and lipidomics, we analyzed plasma from 637 patients with type 2 diabetes (T2D) with confirmed metformin use and 143 nondiabetic controls, annotating 614 metabolites. Patients were stratified by plasma metformin into sub-therapeutic, therapeutic, and supra-therapeutic groups, and associations were evaluated by multiple linear regression and composite metabolite ranking. Five previously unannotated features were structurally identified as N-lactoyl-amino acids, whose levels correlated strongly with plasma metformin (ρ = 0.42–0.55, P &lt; 0.0001) and increased up to 7.2-fold in the supra-therapeutic group (&gt; 2000 ng/mL). While N-lactoyl-amino acids were consistently detected in the nanomolar range, they still displayed robust and dose-dependent associations with metformin. Broader metabolic changes in T2D included elevated lactate, organic acids, and branched-chain amino acids, together with reduced urea cycle metabolites. Lipidomics showed increases in saturated triacylglycerols and diacylglycerols and decreases in cholesteryl esters, sphingomyelins, and phospholipids. These findings establish N-lactoyl-amino acids as robust, dose-responsive plasma biomarkers of metformin exposure. Despite being up to four orders of magnitude less abundant than their amino acid precursors, they sensitively reflect mitochondrial lactate overflow and pharmacodynamic adaptation, offering objective assessment of adherence.

New blood biomarkers reveal how faithfully diabetes patients take metformin

Article

Product

Environment

Food

Health

Scientific article

Science and research

Laboratories

The Czech Academy of Sciences (CAS) was established by Act No. 283/1992 Coll. as the Czech successor of the former Czechoslovak Academy of Sciences. It is set up as a complex of 54 public research institutions.

Czech Academy of Sciences

The Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences (IOCB Prague) is a leading scientific institution in the Czech Republic, recognized internationally. Its primary mission is basic research in the fields of chemical biology and medicinal chemistry, organic and material oriented chemistry, chemistry of natural compounds, biochemistry and molecular biology, physical chemistry, theoretical chemistry, and analytical chemistry. 

Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences

Organomation, founded in 1959, designs and manufactures high-quality nitrogen evaporators and extraction systems. Known for innovation and durability, their lab instruments are used globally for efficient sample preparation with strong customer support.

Organomation

Watrex Streamline OLE 200 On-line SPE system

An automatic on-line solid-phase extraction (SPE) and pre-concentration unit with a 10-port selection valve processes up to 7 samples through 7 SPE cartridges. After washing, the eluted components are directed into an HPLC system via a sample valve. 

Automatic on-line SPE/pre-concentration unit equipped with 10 port selection valve for samples and washing solvents, high pressure cartridge selector for 7 cartridges, high pressure pump, and injection valve connected to HPLC instrument.The pump sucks through 10 port selection valve up to 7 samples to 7 SPE cartridges. Then collected components are washed with one or two slushing eluents, and eluted via sample valve into a HPLC system.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Watrex_Watrex_Streamline_OLE_200_On_line_SPE_system_Principle_of_online_SPE_by_OLE_200_e40db78c8f.jpg" alt="Watrex - Watrex Streamline OLE 200 On-line SPE system - Principle of online SPE by OLE 200"><h3>TECHNICAL SPECIFICATION</h3><ul><li>Cartridge selector: twin 10-port high pressure selector, 40MPa</li><li>Cartridge dimensions: 10x4mm</li><li>Connection to HPLC instrument: Rheodyne 6 port sample valve</li><li>Selector: low-pressure 10-port selection valve IDEX</li><li>Sample load pump: high-pressure single piston ss pump</li><li>Instrument control: driver for all valves and pump controll included</li></ul><h3>Ordering information:</h3><h5>PN/Component:</h5><ul><li>D2K2062401 Watrex OLE200</li></ul>You can also visit this product on the <a target="_blank" rel="noopener noreferrer" href="https://watrex.com/obchod/laboratory-automation/streamline-ole-200/?utm_source=labrulez&amp;utm_medium=propagace&amp;utm_campaign=labrulez_produkty">Watrex website</a>.

Watrex SCS 205 GPC Sample cleanup system

The Watrex Streamline SCS 205 Sample Clean-up System is designed for GPC sample pretreatment.

Sample clean-up is an essential method for many routine chromatography applications. One of the most common cases is analysis of polyaromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and pesticides in complex mixtures.The initial step is an isolation of hydrophobic (lipophilic) components from the rest of the sample mixture by gel-permeation chromatography (GPC).In such configuration, triglycerides (700-900Da) can be isolated from low molecular (200-300Da) PAHs, PCBs or pesticides using GPC steric exclusion. SCS 205 is a dedicated system for GPC sample pretreatment. SCS 205 includes an isocratic pump double piston pump, manual injector with preparative sample loop, PAH/PCB preparative column (200mg sample loading capacity), fraction collector and start-up kit. .The entire system is controlled from a TFT touch display through intuitive screens.After injection and GPC separation, the purified sample (PAHs, PCBs etc.) is captured by an automated fraction collection usinga3-way motorized switching valve. The timing of the collection is predetermined from the elution profile of the pollutants.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Watrex_Watrex_SCS_205_Sample_cleanup_system_column_7dce4f25e0.jpg" alt="Watrex: Watrex SCS 205 Sample cleanup system - column"><h3>FEATURES</h3><ul><li>High performance pollutant izolation from complex matrices</li><li>Eluent flexibility</li><li>Easy programmable</li><li>Easy installation &amp; Simple operation</li></ul><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Watrex_Watrex_SCS_205_Sample_cleanup_system_schema_ad45276ad0.jpg" alt="Watrex: Watrex SCS 205 Sample cleanup system - schema"><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Watrex_Watrex_SCS_205_Sample_cleanup_system_graph_10ce455cc3.jpg" alt="Watrex: Watrex SCS 205 Sample cleanup system - graph"><h3>TECHNICAL SPECIFICATION</h3><ul><li>Sampling System: manual valve</li><li>Sample volume: 2 mL loop</li><li>Fraction collection: 50mL flask</li><li>Collection time programming: alternating valve switching to waste/collect/waste</li><li>Display: 4-character</li></ul><h3>Ordering information:</h3><h5>PN/Component:</h5><ul><li>SCS205-001 SCS 205 Sample Clean-up System (Price 8 627 € ex VAT)</li><li>WI02077 WATREX 250x16 mm PAH Prep column, 10 um</li><li>DGD.3008 WATREX 300x8 mm DeltaGel Mixed-D column, 5 um</li><li>DGB.25020 WATREX 250x20 mm DeltaGel Mixed-B column, 5 um</li></ul>You can also visit this product on the <a target="_blank" rel="noopener noreferrer" href="https://watrex.com/obchod/chromatography/dedicated-instruments/scs-205-sample-clean-up-system/?utm_source=labrulez&amp;utm_medium=propagace&amp;utm_campaign=labrulez_produkty">Watrex website</a>.

Watrex xTrovert XT Automatic DNA/RNA extractor

Watrex xTrovert XT is an automatic DNA/RNA extractor. It streamlines the extraction process, making it more efficient and reproducible.

Automatic extractor utilises a simple principle of two pipetting heads serving a 96-well plate.Thanks to easy replacement head options of pipetting with 300 μl tips or 1000 μl tips are available. Automatic optical sensor calibration enables the use of pipetting tips and 96-well plates from virtually any supplier. The device is equipped with two magnetic arms for protocols including paramagnetic SPR beads. It also allows for thermal incubation in the range of 25 to 85 °C. In addition to internal LED lighting, the station is equipped with an integrated UV-C sterilisation unit. Intuitive control from TFT touch panel user interface facilitates easy set-up. xTrovert™ XT is a fully programmable open system where user can create their own workflow scripts downloadable as text files from USB flas disk.<h3>APPLICATIONS</h3><ul><li>Sample prep for PCR testing</li><li>NGS library prep</li><li>Sanger DNA sequencing</li></ul><h3>CURRENT PROTOCOLS</h3><ul><li>DNA/RNA extraction</li><li>DNA purification</li><li>PCR clean-up/desalting</li></ul><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Watrex_Watrex_x_Trovert_XT_Automatic_DNA_RNA_extractor_Compatible_with_any_magnetic_bead_based_kit_23886eea52.jpg" alt="Watrex: Watrex xTrovert XT Automatic DNA/RNA extractor - Compatible with any magnetic bead based kit"><h3>TECHNICAL SPECIFICATION</h3><ul><li>Capacity: 16 or 32 samples/run</li><li>Volume range: 10 – 600 μl</li><li>Temperature: 25 – 85 °C</li><li>Sterilization: UV-C</li><li>Display: 3,5“ TFT touch display</li><li>Connectivity: USB 1.0/2.0</li><li>Power source: 24 V adaptor</li><li>Dimensions in cm: 65(w) x 65(h) x 34(d)</li><li>Weight: 25 kg</li></ul><h3>Ordering information:</h3><h5>PN/Component:</h5><ul><li>XTR000-001 xTrovert™ XT Universal robotic pipettor for DNA/RNA extraction &amp; handling</li><li>XTR000-003 Replaceable 8-channel 1000uL pipetting head for xTrovert™ XT</li><li>XTR000-004 Replaceable 8-channel 300uL pipetting head for xTrovert™ XT</li><li>XTR000-100 Deepwell plates (empty) for xTrovert™ XT</li><li>XTR000-220 DNA/RNA extraction kit, mgn. beads, 16-rxns per plate</li></ul>The entire system was designed and developed by Watrex Praha and is manufactured in the Czech Republic and promises a shift in the performance and efficiency of laboratory processes worldwide!You can also visit this product on the <a target="_blank" rel="noopener noreferrer" href="https://watrex.com/obchod/laboratory-automation/xtrovert-xt/?utm_source=labrulez&amp;utm_medium=propagace&amp;utm_campaign=labrulez_produkty">Watrex website</a>.

Watrex xTrovert FLEX-O automation SPE sample preparation system

FLEX-O robotic system enabling automation sample preparation on solid phase using 96-titre plates.

FLEX-O robotic system enabling automation sample preparation on solid phase using 96-titre plates. Although there are solutions for automatic SPE on classic column formats, robotic system for automation in 96-well SPE plates is not currently on the market.In addition to the 8-channel pipetting head, the robot is equipped with a gripper and a filling dispenser, which applies wash solutions to the SPE positions on the plate. Instead of filtering using classic vacuum pump, which is used for manual SPE on columns or 96plates, the <a target="_blank" rel="noopener noreferrer" href="https://watrex.com/obchod/laboratory-automation/xtrovert-flex-o/?utm_source=labrulez&amp;utm_medium=propagace&amp;utm_campaign=labrulez_produkty">xTrovert FLEX-O</a> system uses the so-called positive pressure technology when it is the reagent is pushed through the SPE membrane with a multi-channel pressure attachment. That’s it ensuring flow uniformity and reproducibility between individual samples on the plate.The robot is capable of processing up to 4 x 96-well sample plates (384 of total samples) using a protocol with up to 8 different washing and extraction reagents.The system is compatible with the Waters OligoWorks™ SPE Macroplate (96-well), Waters Oasis™ PRiME HLB, Macherey-Nagel™ SPE MULTI 96-Monoblock CHROMABOND™ and other 96-plate format SPE systems.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Watrex_x_Trovert_FLEX_O_automation_SPE_sample_preparation_system_ec3768960e.jpg" alt="Watrex xTrovert FLEX-O automation SPE sample preparation system.jpg" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Watrex_x_Trovert_FLEX_O_automation_SPE_sample_preparation_system_ec3768960e.jpg 208w," sizes="100vw" width="1433" height="1075">If necessary, the user can make modifications to the log using a simple scripting language and subsequent wireless upload to the device. Userthe interface for controlling the system is based on the integrated computer Raspberry Pi ® s 800×480 RGB LCD multi-touch touch screen and the possibility of remote wifi accessfrom an external device (e.g. mobile phone or tablet).<h4>Application</h4><ul><li>Purification of oligonucleotide synthesis products</li><li>Organic Synthesis</li><li>Environmental Analysis</li><li>Medical diagnostics</li><li>Molecular biology and biochemistry</li></ul>The entire system was designed and developed by Watrex Praha and is manufactured in the Czech Republic and promises a shift in the performance and efficiency of laboratory processes worldwide!

Products focused on Sample Preparation from Watrex Prague - page 1

Related content

New blood biomarkers reveal how faithfully diabetes patients take metformin

Steroidal hormones and neurosteroids – novel therapeutic strategies in bacterial infections

EU Regulation 396/2005: Pesticide Residue Testing and the Critical Role of QuEChERS Evaporation in Food Safety