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 Amino HPLC Columns

Achieve excellent chromatographic separations in weak anion exchange, reversed phase and normal phase modes with Thermo Scient

<p><strong>Achieve excellent chromatographic separations in weak anion exchange, reversed phase and normal phase modes with Thermo Scientific™ Hypersil GOLD™ Amino LC Columns. These columns, featuring a high-performance aminopropyl phase, provide outstanding peak shape and sensitivity and are available with a 1.9μm particle size for high speed, high efficiency separations.</strong></p><h5><strong>Excellent Chromatographic Properties in Three Modes</strong></h5><ul><li>Retains anions and organic acids in weak anion exchange mode when used with common buffers and an organic modifier</li><li>Excels for carbohydrate analysis in reversed phase mode</li><li>Offers an alternative selectivity to silica columns in normal phase chromatography</li></ul><h4><strong>Specifications</strong></h4><ul><li><strong>Endcapped:</strong> Yes</li><li><strong>For Use With: </strong>HILIC</li><li><strong>Max. Pressure: </strong>18130 psi (1250 bar)</li><li><strong>Packing Material:</strong> Spherical, Fully Porous, Ultrapure Silica</li><li><strong>Stationary Phase:</strong> Amino (NH2)</li><li><strong>Surface Area:</strong> 220 m²/g</li><li><strong>Temperature:</strong> 60°C</li><li><strong>USP Type: </strong>L8</li><li><strong>Carbon Load</strong>: 2%</li><li><strong>Phase:</strong> Reversed Phase, Normal Phase, Ion Exchange, HILIC</li><li><strong>Pore Size: </strong>175 Å</li><li><strong>pH: </strong>2 to 8</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 Accucore 150 Amide HILIC HPLC Columns

Thermo Scientific™ Accucore™ 150 Amide HILIC LC Columns are ideal for separating hydrophilic biomolecules in HILIC mode, making them an excellent choice for glycan analysis.

<p><strong>Designed for the separation of hydrophilic biomolecules in HILIC mode, Thermo Scientific™ Accucore™ 150 Amide HILIC LC Columns are an excellent choice for glycan separations.Based on Core Enhanced Technology, Thermo Scientific Accucore columns provide fast, high-resolution biomolecule separations—without the elevated backpressures required by sub-2μm particles.</strong></p><ul><li>Rugged and reproducible 2.6μm solid core particles.</li><li>Fast separations with superb resolution</li><li>Low backpressures</li><li>Amide phase bonded onto 150Å pore diameter solid core particles</li><li>High retention of a broad range of hydrophilic analytes in HILIC mode</li><li>Recommended for hydrophilic biomolecules such as glycans</li></ul><h4><strong>Specifications</strong></h4><ul><li><strong>Column type: </strong>HILIC</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> Amide</li><li><strong>Surface Area:</strong> 80 m²/g</li><li><strong>Temperature:</strong> 60°C</li><li><strong>USP Type: </strong>N/A</li><li><strong>Phase:</strong> HILIC</li><li><strong>Pore Size: </strong>150 Å</li><li><strong>pH: </strong>2 to 9</li></ul><h3><strong>Accucore HPLC and UHPLC Columns</strong></h3><h4><strong>Resolve impurities without feeling the pressure</strong></h4><p>Thermo Scientific Accucore HPLC and UHPLC columns provide ultimate core performance, allowing you to maximize your investment. Solid-core particles deliver UHPLC performance, with superb resolution delivering back-pressure compatible with HPLC instrumentation. A wide range of phases help meet all your separation needs, while our columns are exceptionally rugged and easy to use.</p><p><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Thermo_Fisher_Scientific_Accucore_columns_26e0ffa8d5.jpg" alt="Thermo Fisher Scientific: Accucore columns" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Thermo_Fisher_Scientific_Accucore_columns_26e0ffa8d5.jpg 156w," sizes="100vw" width="708" height="711"></p>

Thermo Scientific Syncronis Amino HPLC Columns

Improve the consistency and reliability of your liquid chromatography (LC) separations with Thermo Scientific™ Syncronis™ Amino LC Columns.

<p><strong>Improve the consistency and reliability of your liquid chromatography (LC) separations with Thermo Scientific™ Syncronis™ Amino LC Columns. 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.</strong></p><p>High surface area silica, dense stationary phase coverage and double end-capping minimize secondary interactions and ensure reproducible high-resolution separations.</p><h5><strong>Highly Reproducible Separations</strong></h5><ul><li>Rigorously tested stationary phase bonded to the highest quality silica ensures consistent, predictable LC performance.</li></ul><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>Excellent Performance in Four Modes</strong></h5><ul><li>Aminopropyl phase performs well in reversed phase, normal phase, weak ion exchange and HILIC modes</li></ul><h5><strong>Available in Three Particle Sizes</strong></h5><ul><li>1.7μm for rapid ultrahigh-performance LC (UHPLC) separations</li><li>3μm and 5μm for more traditional HPLC analysis</li></ul><h4><strong>Specifications</strong></h4><ul><li><strong>Column type:</strong> Mixed mode</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> Amino (NH2)</li><li><strong>USP Type:</strong> L8</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> 4%</li><li><strong>Phase:</strong> Reversed Phase, Normal Phase, Ion Exchange, HILIC</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>

Products from category Amino (NH2) HPLC columns focused on LC columns from Thermo Fisher Scientific - page 1

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