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

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

Waters ACQUITY Advanced Polymer Chromatography (APC) System

The ACQUITY APC System Increase sample throughput and laboratory operations by obtaining accurate and repeatable sample separation up to 20 time faster than before.

<div><div><h4><strong>The highest performance for polymers and oligomers</strong></h4></div></div><div><div><p><strong>Today’s polymer scientists operate within an increasingly dynamic market space, one with a growing demand for high-performing materials, bio-material innovations, and intense competition. But the long run times of traditional chromatography polymer characterization has made keeping up with this demand a challenge for many labs.</strong></p><p>Not anymore. With the <strong>next era in polymer separation</strong>, the <strong>ACQUITY Advanced Polymer Chromatography (APC) System</strong>, you can achieve the <strong>highest resolution size-based separations</strong> for <strong>chromatographic polymer and oligomer characterization</strong>, all <strong>faster than ever</strong>. With the <strong>ACQUITY APC System</strong>, you can <strong>improve data consistency and quality</strong> with <strong>fast, daily calibration</strong>, and <strong>automate your method development</strong> with <strong>advanced system technologies</strong> – so you can <strong>innovate faster</strong> while <strong>improving lab operations.</strong></p><div><div><div><div><h3><strong>Features and Benefits</strong></h3><ul><li><strong>Accelerate your insights</strong> - Reduce laboratory turnaround times for polymer samples by getting answers to your development labs, your manufacturing operations teams, and your customers 5 to 20 times faster than traditional SEC/GPC with the ultra-low system dispersion of the ACQUITY APC System paired with <a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/products/1950"><strong>ACQUITY APC Columns</strong></a>.</li><li><strong>Get the accurate data you need for informed decisions</strong> - Gain more insight into your polymer samples through compatibility with a wide range of specific detection techniques (refractive index, UV/Vis, PDA, ELS) and third-party advanced detectors like multi-angle light scattering and viscometry. Get accurate molecular weight (MW) data every day with the precise flow delivery of the isocratic solvent manager.</li><li><strong>Optimize method development, even in harsh conditions</strong> - Optimize method development via rapid and automated solvent switching and aggressive solvent compatibility, which supports the harsh separation conditions associated with polymer analyses.</li><li><strong>Improve lab efficiency with one system</strong> - Increase analytical scope and laboratory efficiency by leveraging one system to perform multiple applications, including basic liquid chromatography (LC), gradient, isocratic, reverse-phase, and gel permeation chromatography (GPC).</li><li><strong>Simplify your column management</strong> - Simplify and optimize column bank calibration through standards that are matched to column bank MW ranges. Versatile column management allows you to automatically select up to two banks of <strong>ACQUITY APC</strong> columns and up to two banks of traditional GPC columns - all housed in a stable, temperature-controlled environment.</li></ul></div></div><div><div><h4><strong>Recommended Use</strong></h4><p>Highest-resolution, size-based separations for chromatographic polymer and oligomer characterization.</p><p><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Waters_ACQUITY_APC_System_nakonfigurovany_pro_automaticke_prepinani_jak_APC_tak_GPC_kolon_e198c774f4/Waters-ACQUITY-APC-System-nakonfigurovany-pro-automaticke-prepinani-jak-APC-tak-GPC-kolon.jpg" alt="Waters ACQUITY Advanced Polymer Chromatography (APC) System." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Waters_ACQUITY_APC_System_nakonfigurovany_pro_automaticke_prepinani_jak_APC_tak_GPC_kolon_e198c774f4/thumbnail_Waters-ACQUITY-APC-System-nakonfigurovany-pro-automaticke-prepinani-jak-APC-tak-GPC-kolon.jpg 213w," sizes="100vw" width="969" height="710"></p><div><div><h3><strong>Accelerate innovation with enhanced insight</strong></h3><p>Harnessing the benefits of advanced polymer chromatography with the ACQUITY APC System means obtaining accurate and repeatable polymer and oligomer molecular weight information anywhere between<strong> 5 to 20 times faster than was possible</strong> with traditional<strong> GPC/SEC technology</strong> - so you can innovate faster while improving laboratory operations.</p><p><strong>With the ACQUITY APC System, you can:</strong></p><ul><li><strong>Reduce laboratory turnaround times for polymer samples&nbsp;</strong>by getting answers to your development labs, your manufacturing operations teams, and your customers - faster.</li><li><strong>Drive innovation</strong>&nbsp;with faster results and more information so that your entire operation can respond more rapidly by decreasing development cycle times and accelerating time to market.</li><li><strong>Streamline process monitoring</strong>&nbsp;and achieve better batch control with the agility to make timely decisions “on-the-fly” about process and synthesis optimization<strong>.</strong></li><li><strong>Significantly reduce the analysis cost per sample</strong>&nbsp;by reducing solvent consumption and waste disposal volumes.</li></ul><p><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Waters_ACQUITY_Advanced_Polymer_Chromatography_APC_System_ca5154865a.jpg" alt="Waters ACQUITY Advanced Polymer Chromatography (APC) System: Accelerate your innovation with enhanced insight into polymer chemical structure with the ACQUITY APC System." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Waters_ACQUITY_Advanced_Polymer_Chromatography_APC_System_ca5154865a.jpg 245w," sizes="100vw" width="1024" height="600"></p><div><div><h3><strong>Optimize method development with solvent switching and compatibility</strong></h3><p>Using the ACQUITY APC System with <strong>Polymer Quaternary Solvent Manager</strong> (p-QSM) <strong>technology </strong>provides chemists and polymer scientists with the ultimate flexibility to analyze the most complex polymer blends and additives using standard polymer chromatography, gradient polymer elution chromatography (GPEC), and reverse-phase LC with a single system.</p><p>Additional system features allow automated solvent selection of up to six different solvents. Automated column bank switching capabilities can also be paired with the rigid and solvent-resilient particles of the <a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/products/1950"><strong>ACQUITY APC Columns</strong></a> to achieve the world’s first truly automated solution for method development of size-based polymer separations. This supports separation of polymers in hours, instead of days.</p><p><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Waters_ACQUITY_Advanced_Polymer_Chromatography_APC_System_2_b95f96f0a2.jpg" alt="Waters ACQUITY Advanced Polymer Chromatography (APC) System: Repeatable analysis of poly (methyl methacrylate co ethylacrylate) using the same two running ACQUITY APC 4.6 x 150 mm Columns (450 Å and 125 Å) in series after automated switching of the solvents from THF to toluene to DMF and back to THF." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Waters_ACQUITY_Advanced_Polymer_Chromatography_APC_System_2_b95f96f0a2.jpg 245w," sizes="100vw" width="1024" height="609"></p></div></div><div><div><h3><strong>Use advanced detection for even more insights</strong></h3><p>Get the valuable decision-making information you need from a single analysis by equipping the ACQUITY APC System with advanced detectors. Combining the ACQUITY APC System with advanced detection solutions significantly increases information attainable from <strong>size-exclusion chromatography</strong> (SEC) analysis through addition of <strong>refractive index</strong> (RI), <strong>ultraviolet </strong>(UV),<strong> photodiode array </strong>(PDA), <strong>light scattering</strong> (LS), and <strong>differential viscometry</strong> (IV). Advanced detection options from <strong>Wyatt Technology</strong> are seamlessly integrated with ACQUITY APC System, enabling you to fully characterize samples to better inform the structure-property relationship of novel complex polymers.</p></div></div><div><div><h3><strong>Keep pace with your research with dedicated consumables</strong></h3><p>The ACQUITY APC System is even more powerful with <a target="_blank" rel="noopener noreferrer" href="https://www.waters.com/nextgen/global/products/columns/acquity-apc-columns.html"><strong>ACQUITY APC Columns</strong></a> and <a target="_blank" rel="noopener noreferrer" href="https://www.waters.com/nextgen/global/products/standards-and-reagents/acquity-advanced-polymer-chromatography-calibration-standards-ki.html"><strong>ACQUITY APC Calibration Standards Kits</strong></a>. The Ethylene Bridged Hybrid (BEH) Technology in ACQUITY APC Columns creates particles that ensure extreme column performance and long column lifetime under harsh operating conditions – ideal for general purpose, reversed-phase chromatography, and for method development due to extreme pH stability and applicability to the broadest range of compound classes.</p><p>With run times of less than 10 minutes, a bank of ACQUITY APC Columns can be <strong>calibrated in less than 30 minutes</strong> using ACQUITY APC Calibration Standards Kits.&nbsp;These standard kits have been matched to the MW range of ACQUITY APC Columns, generating a 10-point calibration for any bank combination in a simple dilute-and-shoot format. With daily column bank calibration, you can greatly improve data consistency to increase confidence in batch-to-batch measurements. Select the best column and calibration standards for a given application with our convenient <a target="_blank" rel="noopener noreferrer" href="https://www.waters.com/waters/promotionDetail.htm?id=134823417">selector tool</a>.&nbsp;</p><p><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Waters_ACQUITY_Advanced_Polymer_Chromatography_APC_System_4_056bb6d284.jpg" alt="Waters ACQUITY Advanced Polymer Chromatography (APC) System: Ethylene Bridged Hybrid (BEH) Technology helps you keep up with the pace of your research with state-of-the-art reversed-phase and HILIC HPLC columns." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Waters_ACQUITY_Advanced_Polymer_Chromatography_APC_System_4_056bb6d284.jpg 245w," sizes="100vw" width="1024" height="620"><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Waters_ACQUITY_Advanced_Polymer_Chromatography_APC_System_5_7a814e249b.jpg" alt="Waters ACQUITY Advanced Polymer Chromatography (APC) System: Improve data and consistency with ACQUITY APC Calibration Standards." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Waters_ACQUITY_Advanced_Polymer_Chromatography_APC_System_5_7a814e249b.jpg 245w," sizes="100vw" width="1024" height="591"></p></div></div></div></div></div></div></div></div></div></div>

Products from category GPC/SEC from Waters distributed by Waters Corporation (Europe) - 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