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

<div><div><p><strong>Researchers led by </strong><a target="_blank" rel="noopener noreferrer" href="https://kudova.group.uochb.cz/en"><strong>Eva Kudová</strong></a><strong> 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 </strong><i><strong>Staphylococcus aureus</strong></i><strong>.</strong></p></div></div><div><p>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.</p><p>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.</p><p>These findings support the idea that rationally designed steroid-based molecules could act as antibiotic adjuvants, helping existing drugs overcome bacterial resistance.</p><p><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"></p><blockquote><h4><strong>Original Article</strong></h4><h4><a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0223523426001613?via%3Dihub"><strong>Steroidal hormones and neurosteroids - novel therapeutic strategies in bacterial infections: Design, synthesis, and biological evaluation</strong></a></h4><p>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;</p><p><i><strong>Eur. J. Med. Chem., 2026, 308, 118716</strong></i></p><p><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></p><h6>licensed under <a target="_blank" rel="noopener noreferrer" href="https://creativecommons.org/licenses/by/4.0/"><strong>CC-BY 4.0</strong></a></h6></blockquote><h4><strong>Abstract</strong></h4><p>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 <i>Staphylococcus aureus</i>. Structure-activity relationship analysis identified compounds <strong>13</strong> and <strong>16</strong> 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 <strong>13</strong> significantly downregulated <i>S. aureus</i> 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.</p><h4><strong>Instrumentation</strong></h4><h5><strong>Structural characterization</strong></h5><ul><li><strong>AVANCE III 400 MHz NMR spectrometer</strong> (Bruker)</li><li><a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/library?mainauthorItems=3&amp;search=LTQ+Orbitrap+XL"><strong>LTQ Orbitrap XL HRMS</strong></a> (Thermo Fisher Scientific, ESI)</li></ul></div>

Steroidal hormones and neurosteroids – novel therapeutic strategies in bacterial infections

<p><strong>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.</strong></p><h4><strong>New biomarkers for metformin use</strong></h4><p>A team led by Tomáš Čajka from the Laboratory of Translational Metabolism at IPHYS analyzed plasma samples from <strong>637 patients with type 2 diabetes treated with metformin</strong> and <strong>143 non-diabetic controls</strong> using advanced metabolomics and lipidomics. Among 614 detected metabolites, they identified five from the group of <strong>N-lactoyl-amino acids </strong>(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.</p><h4><strong>A sensitive “fingerprint” of the drug’s effect</strong></h4><p>N-Lactoyl-amino acids are formed in cells by combining lactate and amino acids, thus reflecting the metformin-induced changes in cellular energy metabolism. “<i>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</i>,” emphasizes T. Čajka.</p><h4><strong>Metabolomics in practice and international collaboration</strong></h4><p>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 <strong>Clinical and Experimental Medicine in Prague</strong> and the <strong>West Coast Metabolomics Center</strong> (University of California, Davis) also participated in the study.</p><p>The results demonstrate that advanced metabolomics approaches developed at IPHYS within the <strong>CarDia project</strong> can find highly practical applications both in clinical studies and in personalized monitoring of treatment in patients with diabetes.</p><blockquote><h4><strong>The original article</strong></h4><h4><a target="_blank" rel="noopener noreferrer" href="https://ascpt.onlinelibrary.wiley.com/doi/10.1002/cpt.70205"><strong>Untargeted Metabolomics Identifies N-Lactoyl-Amino Acids as Dose-Responsive Plasma Biomarkers of Metformin Adherence in Type 2 Diabetes</strong></a></h4><p>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 Haluzik</p><p>Clin Pharmacol Ther, 119: 1057-1069</p><p><a target="_blank" rel="noopener noreferrer" href="https://doi.org/10.1002/cpt.70205">https://doi.org/10.1002/cpt.70205</a></p><h6>licensed under <a target="_blank" rel="noopener noreferrer" href="https://creativecommons.org/licenses/by/4.0/"><strong>CC-BY 4.0</strong></a></h6></blockquote><h4><strong>Abstract</strong></h4><p>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.</p>

New blood biomarkers reveal how faithfully diabetes patients take metformin

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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.

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Thermo Scientific™ Dionex™ Easion™ Ion Chromatography System

Compact IC system with built-in suppressor, heated conductivity detection, and automated sample handling—ideal for routine anion and cation analysis in water and environmental labs.

<h4><strong>Compact, intuitive IC system for routine anion and cation analysis</strong></h4><p><strong>The Dionex Easion IC system is a small yet powerful ion chromatography solution designed for routine water and environmental analysis. With its compact footprint, easy setup, and intuitive Chromeleon™ CDS control, the system enables fast, reliable quantification of both anions and cations—even for inexperienced users. Built-in chemical suppression, minimal maintenance, and preconfigured analysis kits make it ideal for any lab performing standard IC workflows.</strong></p><h3><strong>Key Features and Benefits</strong></h3><h4>🧪 <strong>Simple, Complete System</strong></h4><ul><li>Fully integrated setup includes suppressor, columns, eluent and regenerant concentrates</li><li>Ready to operate in under <strong>90 minutes</strong>—no extra pumps or accessories needed</li><li>Compatible with 2, 3, and 4 mm anion and cation columns</li></ul><h4>📏 <strong>Reliable, Reproducible Performance</strong></h4><ul><li><strong>Heated bipolar conductivity cell</strong> ensures signal stability and low noise</li><li>Chemical suppression with <strong>Dionex CRS 500</strong> suppressor—no regeneration steps needed</li><li>Fixed-loop valve for <strong>manual or automated injections</strong></li><li>Flow range: 0.01–5.00 mL/min; pressure up to 5000 psi</li></ul><h4>💡 <strong>Smart and Compact Design</strong></h4><ul><li>All-PEEK flow path—metal-free and chemically inert</li><li>Simple eluent preparation with concentrates and high-purity water</li><li>Bench-friendly size (33 × 24 × 40 cm, 10 kg) with minimal maintenance</li></ul><h4>🔁 <strong>Automation Ready</strong></h4><ul><li>Supports <strong>Dionex AS-DV, AS-AP, and AS-HV autosamplers</strong></li><li>Built-in sample filtration (with AS-DV) and dilution workflows</li><li>Autosampler-based inline filtration and degassing options available</li></ul><h4>🧠 <strong>Controlled by</strong><a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/products/76"><strong> Chromeleon™ CDS</strong></a></h4><ul><li>Intuitive system setup with ProcedureWizards™ and application templates</li><li>Built-in calibration memory and audit trail</li><li>Virtual column simulator and multi-vendor instrument integration</li></ul><h3><strong>Applications</strong></h3><ul><li><strong>Drinking water</strong> and <strong>wastewater</strong> monitoring</li><li><strong>Inorganic ion analysis</strong> (F⁻, Cl⁻, NO₃⁻, PO₄³⁻, SO₄²⁻, etc.)</li><li><strong>Routine ammonium and cation detection</strong> (Li⁺, Na⁺, NH₄⁺, Ca²⁺...)</li><li><strong>Educational and QA/QC laboratories</strong></li></ul><p><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Thermo_Dionex_Easion_System_news_1f1d3e6c64/Thermo-Dionex-Easion-System-news.jpg" alt="Thermo Scientific™ Dionex™ Easion™ Ion Chromatography System" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Thermo_Dionex_Easion_System_news_1f1d3e6c64/thumbnail_Thermo-Dionex-Easion-System-news.jpg 215w," sizes="100vw" width="1103" height="800"></p>

Thermo Scientific Vanquish Core HPLC System

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Thermo Scientific™ Vanquish™ Neo UHPLC System

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Thermo Scientific™ Dionex™ Aquion™ Ion Chromatography (IC) System

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<h4><strong>Reliable, budget-friendly ion chromatography for routine anion and cation analysis</strong></h4><p>Simplify ion analysis in your laboratory with the <strong>Dionex™ Aquion™ IC system</strong>, a compact and easy-to-operate platform designed for routine applications in <strong>environmental, food safety, and academic labs</strong>. Ideal for budget-conscious operations, the Aquion system delivers dependable performance, quick startup, and low operating costs.</p><h3><strong>Key system features</strong></h3><ul><li><strong>Chemically inert PEEK flow path</strong></li><li><strong>Serial dual-piston pump</strong><ul><li>Flow rate: 0.01–5.0 mL/min</li><li>Pressure: up to 5000 psi</li></ul></li><li><strong>High-pressure pulse dampener</strong></li><li><strong>Electrically actuated, PEEK, 6-port Rheodyne injection valve</strong></li><li><strong>Conductivity detection with digital signal processing</strong><ul><li>Range: 0–15,000 μS</li><li>Temperature-controlled conductivity cell for signal stability</li></ul></li><li><strong>Support for electrolytic or chemical suppressors</strong></li><li><strong>Optional column heater</strong></li><li><strong>Built-in inline vacuum degasser</strong></li></ul><h3><strong>Benefits of electrolytic suppression</strong></h3><ul><li>Lower background conductivity and reduced detection limits</li><li>Faster system startup</li><li>Superior sensitivity for both anion and cation analysis</li><li>No need for manual regenerant preparation</li></ul><h3><strong>Optimized detection with conductivity</strong></h3><p>The Aquion system is optimized for conductivity detection using a <strong>thermostated high-performance cell</strong> that ensures stability against ambient temperature fluctuations. Digital signal control offers a wide dynamic range for simultaneous detection of analytes with varying concentrations.</p><h3><strong>Seamless control with Chromeleon™ CDS software</strong></h3><p>Included in every system bundle, <a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/products/76"><strong>Thermo Scientific™ Chromeleon™ Chromatography Data System (CDS)</strong></a> software provides intuitive instrument control, automated workflows, and streamlined data handling:</p><ul><li><strong>eWorkflows</strong>: auto-load instrument conditions and processing templates</li><li><strong>Calibration Wizard</strong>: step-by-step guidance for method setup and quantification</li><li><strong>Wellness Trending</strong>: monitor system performance over time for predictive maintenance</li></ul><h3><strong>Anion and Cation System Bundles</strong></h3><p>Each bundle includes everything needed to get started:</p><h4><strong>Included in all system bundles:</strong></h4><ul><li>Dionex Aquion IC System with power cable</li><li>Dionex Aquion Analysis Kit (anion or cation specific)</li><li>Chromeleon SE software and license</li><li>3-year warranty (parts-only coverage in years 2 and 3)<br>→ Optional extended warranty available including labor and travel in years 2 and 3</li></ul><h4><strong>Anion Analysis Kit includes:</strong></h4><ul><li><strong>Dionex IonPac AG22 (4 × 50 mm) guard column</strong></li><li><strong>Dionex IonPac AS22 (4 × 250 mm) analytical column</strong></li><li><strong>Dionex AERS 500 Carbonate (4 mm) suppressor</strong></li><li><strong>Combined Seven Anion Standard II</strong><br><i>Note: Eluent concentrate must be ordered separately.</i></li></ul><h4><strong>Cation Analysis Kit includes:</strong></h4><ul><li><strong>Dionex IonPac CG12A (4 × 50 mm) guard column</strong></li><li><strong>Dionex IonPac CS12A (4 × 250 mm) analytical column</strong></li><li><strong>Dionex CDRS 600 (4 mm) suppressor</strong><br><i>Note: Eluent concentrate and standards must be ordered separately.</i></li></ul><h3><strong>Why choose Dionex Aquion?</strong></h3><ul><li>Proven IC platform with straightforward operation</li><li>Reliable results and stable performance</li><li>Full compatibility with standard and microbore column formats (2–5 mm)</li><li>Low cost of ownership with high-quality support and service</li><li>Ideal entry point for labs new to ion chromatography</li></ul><p><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Thermo_Dionex_Aquion_Iontovy_Chromatograf_2_8c661a76f1/Thermo-Dionex-Aquion-Iontovy-Chromatograf-2.jpg" alt="Thermo Scientific™ Dionex™ Aquion™ Ion Chromatography (IC) System" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Thermo_Dionex_Aquion_Iontovy_Chromatograf_2_8c661a76f1/thumbnail_Thermo-Dionex-Aquion-Iontovy-Chromatograf-2.jpg 156w," sizes="100vw" width="650" height="650"></p>

Thermo Scientific™ Dionex™ ICS-4000 Capillary HPIC™ System

Capillary HPIC system for high-resolution, reagent-free ion chromatography with 24/7 readiness, ultra-low eluent use, and versatile detection in a compact format.

<h4><strong>Always on, always ready — high-resolution capillary IC in a compact platform</strong></h4><p>The <strong>Dionex ICS-4000</strong> is the world’s first <strong>dedicated capillary high-pressure reagent-free ion chromatography (HPIC) system</strong>. Designed for high-resolution, low-flow separations, it delivers exceptional chromatographic performance, fast analysis times, and 24/7 on-demand readiness. With integrated control, capillary-optimized detectors, and minimal eluent consumption, it offers a new standard for reliable, low-maintenance ion chromatography.</p><h3><strong>Key Features and Benefits</strong></h3><h4>🧪 <strong>Capillary HPIC Performance</strong></h4><ul><li>Supports <strong>high-pressure separations</strong> with 4 µm columns</li><li><strong>Fast, high-resolution gradients</strong> in minutes</li><li>Continuous operation with <strong>no equilibration needed</strong></li></ul><h4>♻️ <strong>Reagent-Free Simplicity</strong></h4><ul><li><strong>Eluent generation</strong> from deionized water via EGC cartridge</li><li>Just <strong>15 mL of water/day</strong> for continuous operation</li><li>Eluent cartridges last up to <strong>18 months</strong></li></ul><h4>🧠 <strong>Integrated Smart Design</strong></h4><ul><li>Fully integrated system in <strong>compact footprint</strong></li><li><strong>Tilt-up lid</strong>, color-coded connections, and pre-cut tubing</li><li><strong>Vacuum degassing</strong>, seal wash (option), and inline shut-off valves</li></ul><h4>🧲 <strong>Versatile Detection Options</strong></h4><ul><li><strong>Conductivity Detector (CD)</strong> – with self-regenerating suppressor</li><li><strong>Electrochemical Detector (ED)</strong> – ideal for cyanide, amines, carbohydrates</li><li><strong>QD Charge Detector</strong> – signal proportional to ion charge and concentration</li></ul><h4>🔁 <strong>Flexible Column Chemistry</strong></h4><ul><li>Compatible with <strong>over 20 capillary columns</strong></li><li>Suitable for a wide range of inorganic and organic ions, sugars, acids, amines</li></ul><p><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Thermo_Dionex_ICS_4000_Iontovy_Chromatograf_2_64107dbdca/Thermo-Dionex-ICS-4000-Iontovy-Chromatograf-2.jpg" alt="Thermo Scientific™ Dionex™ ICS-4000 Capillary HPIC™ System" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Thermo_Dionex_ICS_4000_Iontovy_Chromatograf_2_64107dbdca/thumbnail_Thermo-Dionex-ICS-4000-Iontovy-Chromatograf-2.jpg 156w," sizes="100vw" width="650" height="650"></p><h3><strong>Automation and Sample Handling</strong></h3><ul><li>Compatible with <strong>Dionex AS-DV</strong> and <strong>AS-AP</strong> autosamplers</li><li>Advanced prep (dilution, derivatization, matrix removal)</li><li>Supports <strong>vials, well plates</strong>, and &lt;30 s injection cycles</li><li>Optional <strong>Sample Conductivity &amp; pH Accessory</strong> with conditional logic</li></ul><h3><strong>Software Integration</strong></h3><ul><li>Controlled by <a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/products/76"><strong>Chromeleon™ Chromatography Data System (CDS)</strong></a></li><li>eWorkflows™ simplify analysis from injection to report</li><li>Interactive charts and MiniPlots for intuitive data interpretation</li></ul><h3><strong>Ideal for Applications in</strong></h3><ul><li>Food and beverage (e.g., sugars, organic acids, preservatives)</li><li>Environmental (e.g., drinking water, wastewater)</li><li>Pharmaceutical (e.g., excipients, counterions)</li><li>Educational and routine analytical labs</li></ul>

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