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 Hypersil GOLD C8 HPLC Columns

For analytes with medium hydrophobicity or when a less hydrophobic phase is required to obtain optimum retention, use Thermo Scientific™ Hypersil GOLD™ C8 LC columns

<p><strong>For analytes with medium hydrophobicity or when a less hydrophobic phase is required to obtain optimum retention, use Thermo Scientific™ Hypersil GOLD™ C8 LC columns for outstanding sensitivity and excellent peak shape. The selectivity is similar to C18 columns with a predictable elution order but less retention. The lower hydrophobicity allows compounds to elute more quickly, yielding faster separations.</strong></p><h5><strong>Similar selectivity, less retention than C18 columns</strong></h5><ul><li>Successful retention and separation of moderately hydrophobic analytes</li><li>Ideal for fatty acids, which are too hydrophobic for analysis using C18 columns</li></ul><h5><strong>Faster separations</strong></h5><ul><li>Higher analytical throughput compared to C18 alkyl chain chemistry</li><li>Quicker compound elution due to reduced hydrophobic interactions</li></ul><h5><strong>Superior performance</strong></h5><ul><li>Highly symmetrical peak shapes</li><li>Improved speed of analysis, efficiency, and sensitivity</li></ul><h4><strong>Specifications</strong></h4><ul><li><strong>Endcapped:</strong> Yes</li><li><strong>Max. Pressure: </strong>5800 psi (400 bar)</li><li><strong>Packing Material:</strong> Spherical, Fully Porous, Ultrapure Silica</li><li><strong>Stationary Phase:</strong> C8</li><li><strong>Surface Area:</strong> 220 m²/g</li><li><strong>Temperature:</strong> 60°C</li><li><strong>USP Type: </strong>L7</li><li><strong>Carbon Load</strong>: 8%</li><li><strong>Phase:</strong> Reversed Phase</li><li><strong>Pore Size: </strong>175 Å</li><li><strong>pH: </strong>2 to 9</li></ul><h4><strong>About the Hypersil GOLD Family of HPLC Columns</strong></h4><p>Meet the challenges of modern chromatography with state-of-the-art columns that provide outstanding performance and consistent separations. <strong>Twelve different column chemistries</strong> are available so you can optimize separations and maximize productivity. Get outstanding peak shapes in reversed phase, ion exchange, HILIC, or normal phase chromatography.</p><p><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Thermo_Fisher_Scientific_Hypersil_GOLD_Columns_41d5984b62.jpg" alt="Thermo Fisher Scientific: Hypersil GOLD Columns" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Thermo_Fisher_Scientific_Hypersil_GOLD_Columns_41d5984b62.jpg 150w," sizes="100vw" width="747" height="775"></p><ul><li><strong>Excellent peak symmetry</strong><ul><li>Hypersil GOLD columns <strong>produce highly symmetrical peaks</strong>, which facilitate the detection of low-level impurities that elute immediately after the main component. When there is even minor tailing, small impurity peaks can elute on the shoulder of the main peak, complicating the integration process.</li></ul></li><li><strong>Narrow peaks </strong>for outstanding efficiency</li><li><strong>Enhanced sensitivity</strong> and improved resolution</li><li><strong>Exceptional reproducibility </strong>for reliable chromatography, column after column</li><li>Solutions for <strong>high-throughput screening</strong></li><li><strong>1.9, 3, and 5 μm particle sizes </strong>for all your separation needs</li></ul><p><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Thermo_Fisher_Scientific_Hypersil_GOLD_Peak_symmetry_641b946673.jpg" alt="Thermo Fisher Scientific: Hypersil GOLD Columns: Peak symmetry" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Thermo_Fisher_Scientific_Hypersil_GOLD_Peak_symmetry_641b946673.jpg 149w," sizes="100vw" width="880" height="925"></p>

Thermo Scientific Acclaim 120 C8 HPLC Columns

For reversed-phase separation of analytes with moderate hydrophobicity, use Thermo Scientific™ Acclaim™ 120 C8 LC columns.

<p><strong>For reversed-phase separation of analytes with moderate hydrophobicity, use Thermo Scientific™ Acclaim™ 120 C8 LC columns. These high-performance columns provide selectivity that is similar to Acclaim 120 C18 columns with a predictable elution order but less retention. Compounds elute more quickly, yielding faster separations. The unique chemistry of densely bonded C8 ligands on an ultrapure, spherical, porous silica substrate gives the Acclaim 120 C8 columns excellent efficiencies.</strong></p><h5><strong>High Performance Reversed-Phase Columns for the Separation of Small Molecules</strong></h5><ul><li>Low silanol activity for excellent peak shapes</li><li>Reproducible column-to-column performance</li><li>Extremely low bleed, fully compatible with MS</li><li>Stable between pH 2 and 8</li><li>Available in 2.2, 3, and 5μm particle sizes and 4.6, 3.0, and 2.1mm diameters, with an average pore diameter of 120Å</li><li>Also available in 2.2μm RSLC format for reliable, fast separations</li></ul><h4><strong>Specifications</strong></h4><ul><li><strong>Endcapped:</strong> Yes</li><li><strong>Max. Pressure: </strong>4500 psi (310 bar)</li><li><strong>Packing Material:</strong> Spherical, Porous, Ultrapure Silica</li><li><strong>Stationary Phase:</strong> C8</li><li><strong>Surface Area:</strong> 300 m²/g</li><li><strong>Temperature:</strong> 60°C</li><li><strong>USP Type: </strong>L7</li><li><strong>Carbon load:</strong> 11%</li><li><strong>Phase:</strong> Reversed phase</li><li><strong>Pore Size: </strong>120 Å</li><li><strong>pH: </strong>2 to 8</li></ul><h4><strong>About the Acclaim Family of HPLC Columns</strong></h4><p>Achieve the high standards set by modern HPLC and LC/MS methods with the Acclaim family of reversed-phase columns. These silica-based columns with advanced column bonding and endcapping technologies provide complementary selectivity, high column efficiencies, and ultra-high resolution for a wide variety of applications.</p><ul><li>Broad spectrum of stationary phases, including conventional C8 and C18 phases, polar embedded phases, and specialty phases including wide-pore, are available to meet your specific application needs</li><li>Performance tested to ensure high quality and reliability for pharmaceutical, biopharmaceutical, environmental, food, and other industrial chromatographic separations</li></ul><p><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Thermo_Fisher_Scientific_Acclaim_column_Broad_range_of_HPLC_and_UHPLC_columns_2ec9c98a86.jpg" alt="Thermo Fisher Scientific: Broad range of HPLC and UHPLC columns" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Thermo_Fisher_Scientific_Acclaim_column_Broad_range_of_HPLC_and_UHPLC_columns_2ec9c98a86.jpg 191w," sizes="100vw" width="1172" height="958"></p>

Thermo Scientific Syncronis C8 HPLC Columns

Improve the consistency and reliability of your liquid chromatography (LC) separations using Thermo Scientific™ Syncronis™ C8 LC columns.

<p><strong>Improve the consistency and reliability of your liquid chromatography (LC) separations using Thermo Scientific™ Syncronis™ C8 LC columns. High-purity, high surface area silica and dense stationary phase coverage minimize secondary interactions and deliver reproducible, high-efficiency separations.&nbsp;</strong></p><p>Double end-capping provides extra surface coverage and inertness toward basic compounds. Manufactured and rigorously tested in ISO 9000 facilities, these columns are designed to meet a range of analytical needs including fast method development, quantitative analysis, and quality control where less retention is required than when using a C18 column.</p><h5><strong>Excellent Peak Shapes for Enhanced Resolution and Sensitivity</strong></h5><ul><li>Dense surface coverage of silica minimizes secondary interactions and peak tailing</li><li>Double endcapped for extra surface coverage</li></ul><h5><strong>Exceptional Column-to-Column Consistency</strong></h5><ul><li>Manufactured, packed, and tested in ISO-9000-accredited facilities</li><li>Every column individually tested to meet stringent retention, efficiency, and peak symmetry specifications</li><li>Enhanced automated packing process</li></ul><h5><strong>Lower Hydrophobic Retention</strong></h5><ul><li>Recommended for moderately hydrophobic analytes or for when a less hydrophobic phase provides optimum retention</li></ul><h5><strong>Available in Three Particle Sizes</strong></h5><ul><li>1.7 μm for rapid ultrahigh-performance LC (UHPLC) separations, and 3 μm and 5 μm for more traditional HPLC analysis</li></ul><h4><strong>Specifications</strong></h4><ul><li><strong>Column type:</strong> Reversed Phase</li><li><strong>Endcapped:</strong> yes</li><li><strong>Max. Pressure:</strong> 5800 psi (400 bar)</li><li><strong>Packing Material:</strong> Spherical, Fully Porous, Ultrapure Silica</li><li><strong>Stationary phase:</strong> C8</li><li><strong>USP Type:</strong> L7</li><li><strong>Surface Area:</strong> 320 m<sup>2</sup>/g</li><li><strong>Temperature:</strong> 60°C</li><li><strong>Carbon load: </strong>10%</li><li><strong>Phase:</strong> Reversed Phase</li><li><strong>Pore Size: </strong>100 Å</li><li><strong>pH: </strong>2 to 8</li></ul><h4><strong>Syncronis HPLC and UHPLC Columns</strong></h4><h5><strong>Enter a new world of chromatography</strong></h5><p>When developing a new method, one of the most important goals for the chromatographer is to achieve a consistent, reproducible separation. This makes selecting an HPLC column that offers highly-reproducible results essential to attaining this goal.</p><h5><strong>Features of Syncronis columns</strong></h5><p>Thermo Scientific Syncronis LC columns achieve high levels of consistency and reproducibility through:</p><ul><li>Highly-pure, high-surface-area silica</li><li>Dense bonding and double endcapping</li><li>Stringent manufacturing and testing protocols</li></ul>

Thermo Scientific Accucore C8 HPLC Columns

Improve separation speed and resolution while maintaining low backpressures using Thermo Scientific™ Accucore™ C8 LC Columns. 

<p><strong>Improve separation speed and resolution while maintaining low backpressures using Thermo Scientific™ Accucore™ C8 LC Columns. Rugged 2.6μm solid-core particles ensure high efficiencies and enable compatibility with both HPLC and UHPLC platforms.&nbsp;</strong></p><p>The high coverage C8 bonded phase provides optimal retention of analytes with moderate hydrophobicity. Robust bonding technology and automated packing procedures ensure excellent reproducibility and long column lifetimes.</p><h5><strong>Lower Hydrophobic Retention</strong></h5><ul><li>Recommended for moderately hydrophobic analytes or for when a less hydrophobic phase provides optimum retention</li></ul><h5><strong>Fast Separations</strong></h5><ul><li>2.6μm core-enhanced technology particles enable operation at high flow rates without generating excessive backpressures.</li></ul><h5><strong>Excellent Peak Shapes for Enhanced Resolution and Sensitivity</strong></h5><ul><li>Solid core 2.6μm particles and narrow particle size distribution reduce band broadening and improve separation efficiencies.</li><li>High surface coverage of silica minimizes secondary interactions and peak tailing.</li></ul><h5><strong>Low Backpressures</strong></h5><ul><li>Solid core 2.6μm particles for less backpressure compared to UHPLC sub-2μm particles</li><li>Compatible with conventional HPLC instrumentation and UHPLC platforms</li></ul><h5><strong>Excellent Reproducibility and Robustness</strong></h5><ul><li>Advanced bonding technology</li><li>Automated packing process</li></ul><h4><strong>Specifications</strong></h4><ul><li><strong>Endcapped:</strong> Yes</li><li><strong>For Use With:</strong> HPLC</li><li><strong>Max. Pressure: </strong>14500 psi (1000 bar)</li><li><strong>Packing Material:</strong> Spherical, Solid Core, Ultrapure Silica</li><li><strong>Stationary Phase:</strong> C8</li><li><strong>Surface Area:</strong> 130 m²/g</li><li><strong>Temperature:</strong> 70°C</li><li><strong>USP Type: </strong>L7</li><li><strong>Carbon Load</strong>: 5%</li><li><strong>Phase:</strong> Reversed Phase</li><li><strong>Pore Size: </strong>80 Å</li><li><strong>pH: </strong>2 to 9</li></ul>

Products from category C8 HPLC columns from Thermo Fisher Scientific - page 1

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New blood biomarkers reveal how faithfully diabetes patients take metformin

Steroidal hormones and neurosteroids – novel therapeutic strategies in bacterial infections

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