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

SIELC Alltesta Mini HPLC Autosampler

The Alltesta™ Mini Autosampler is an affordable and dependable solution for automated sample handling in various analytical and liquid handling applications, including HPLC.

<p><strong>The Alltesta™ Mini Autosampler is an affordable and dependable solution for automated sample handling in various analytical and liquid handling applications, including HPLC. With its proprietary alpha/beta mechanical design, this compact autosampler offers direct and comprehensive control of its features, making integration quick and easy. Users can tailor the mini autosampler to their needs with customizable valve configurations, tray designs, and syringe volumes and pressures. Additionally, a built-in shaking feature enables sample mixing before injection and/or simple sample extraction within the vial.</strong></p>
<p>This compact autosampler comes designed with original equipment manufacturer (OEM) customization in mind. Custom shape, color, and communication interfaces can be adapted to integrate with any system. Comprehensive software integration support is provided. Other options include metal-free sampling and reagent addition and mixing capabilities.</p>
<ul>
<li><p><strong>FRACTION COLLECTION CAPABILITY:</strong> A simple software modification can quickly convert this small autosampler into a fraction collector.</p>
</li>
<li><p><strong>REACTOR PROBE SAMPLER CAPABILITY:</strong> A simple software modification can quickly convert this small autosampler into a reactor probe sampler.</p>
</li>
</ul>
<p>This miniature autosampler can also be used as a component of our <a href="https://lcms.labrulez.com/products/1242"><strong>Alltesta™ Gradient Automated Analyzer</strong></a> and <a href="https://lcms.labrulez.com/products/1243"><strong>Alltesta™ Cromite Analyzer</strong></a>.</p>
<blockquote>
<h4><strong>The price of the Alltesta™ Mini Autosampler varies depending on the specific configuration requested.</strong></h4>
</blockquote>
<h4><strong>Specifications</strong></h4>
<ul>
<li>Dimensions (WHL): 160 x 145 x 195 mm / 6.3 x 5.71 x 7.68 in</li>
<li>Weight: 3 kg / 6.6 lb</li>
<li>Power: 24 V</li>
<li>Capacity: 48 vials or 96-well plate</li>
<li>Pressure: 5000 psi</li>
<li>Needle Wash: Inside and outside</li>
<li>Syringe Capacity: 120µL high-pressure / 4000µL low-pressure stainless / 4000µL low-pressure ceramic</li>
<li>Valve options: 6×2, 7×6 and 10×9 (more details here).</li>
<li>Volume Accuracy: 0.1µL</li>
<li>Communication: RS232 Virtual COM port via USB</li>
</ul>
<p><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/SIELC_Alltesta_Mini_Autosampler_A_very_simple_schematic_operation_of_the_Alltesta_Autosampler_b79b0ad187.jpg" alt="SIELC: Alltesta™ Mini Autosampler - A very simple schematic operation of the Alltesta™ Autosampler."/></p>
<h4><strong>Software</strong></h4>
<p>The Alltesta™ Autosampler can be controlled:</p>
<ul>
<li>directly via serial commands (Alltesta™ protocol available upon request, please contact us at support@sielc.com),</li>
<li>directly via our demo software, allowing to learn the whole functionality of the unit (<a href="https://sielc.com/wp-content/uploads/2022/12/Alltesta_Autosampler_Control_Windows_10.zip"><strong>Windows 10, 32/64bit</strong></a>, 5Mb; <a href="https://sielc.com/wp-content/uploads/2022/12/Alltesta_Autosampler_Control_Windows_7.zip"><strong>Windows 7, 32/64bit</strong></a>, 126Mb).</li>
<li>remotely through our cloud software (as a part of Alltesta™ Analyzer or Alltesta™ Mini Analyzer),</li>
</ul>
<p>Serial communication drivers are available <a href="https://ftdichip.com/drivers/vcp-drivers/"><strong>here</strong></a>.</p>


SIELC Alltesta™ Mini LHS (Liquid Handling Station)

The Alltesta™ Mini Liquid Handling Station serves as an affordable, reliable solution for automated sample handling.

<p><strong>The Alltesta™ Mini Liquid Handling Station serves as an affordable, reliable solution for automated sample handling. With its compact design, proprietary alpha/beta mechanical structure, and adjustable operation speeds, it offers comprehensive control for quick and seamless integration with other equipment. The station comes equipped with a built-in sample shaking feature for in-vial sample mixing and extraction, and a needle washing station capable of accommodating up to four solvents.</strong></p>
<p>Designed with Original Equipment Manufacturer (OEM) customization in mind, the Alltesta™ Mini Liquid Handling Station can be tailored to fit any system’s requirements. Custom needle lengths and trays enable the device to accommodate various types of vials. An array of integrated valves and a measuring syringe can be added to the device. Additional customization options, such as metal-free flow paths and customer-specified enclosure colors, are also available.</p>
<p>Comprehensive software integration support is provided to ensure smooth operation and functionality.</p>
<h4><strong>Specifications</strong></h4>
<ul>
<li>Dimensions (WHL): 160 x 145 x 195 mm / 6.3 x 5.71 x 7.68 in</li>
<li>Weight: 2.25 kg / 5 lb</li>
<li>Power: 24 V</li>
<li>Capacity: 48-vial tray or 96-well plate</li>
<li>Needle Wash: Inside and Outside</li>
<li>Communication: RS232 Virtual COM port via USB</li>
</ul>
<h4><strong>Software</strong></h4>
<p>The Alltesta™ LHS can be fully controlled via serial commands. Alltesta™ protocol available upon request, please contact us at support@sielc.com. Serial communication drivers are available <a href="https://ftdichip.com/drivers/vcp-drivers/"><strong>here</strong></a>.</p>


Watrex Streamline FC1 Fraction Collector

The fully automated fraction collector FC1 offers a universal solution for a number of applications requiring the collection of fractions, e.g. protein purification, preparative chromatography.

<p><strong>The fully automated fraction collector FC1 offers a universal solution for a number of applications requiring the collection of fractions, e.g. protein purification, preparative chromatography or other methods for obtaining samples by fractionation.</strong></p><blockquote><p><span style="font-size:18px;"><strong>Price: 4 260</strong><bdi><span class="wmc-cache-pid woocommerce-Price-amount amount" data-wmc_product_id="24487"><strong>&nbsp;</strong></span><span class="wmc-cache-pid woocommerce-Price-amount amount woocommerce-Price-currencySymbol" data-wmc_product_id="24487"><strong>€ ex VAT</strong></span></bdi></span></p></blockquote><p>For advanced programming and connection to chromatography software, the device is equipped with a <strong>USB interface</strong>. FC1 is supported by the <a target="_blank" rel="noopener noreferrer" href="https://lcms.cz/products/305"><strong>Clarity Chromatography Station</strong></a></p><p><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Watrex_schema_procesu_sberu_frakci_pomoci_frakcni_kolektor_FC_1_fa579d59f2/Watrex-schema-procesu-sberu-frakci-pomoci-frakcni-kolektor-FC1.png" alt="Watrex: Schematic of the fraction collection process using the FC1 fraction collector"></p><p>The <strong>robust</strong> design of the FC1 ensures reliable X-Y displacement that carries the switching valve. Placing the fraction switch directly above the receiving vessel <strong>minimizes dead volume between fractions</strong>.</p><p>Depending on the <strong>required volume of fractions</strong>, different types of test tube stands are offered with the device. Furthermore, it is also possible to use large-volume containers.</p><p>The operator controls and programs the fraction collector from the <strong>touch screen</strong> on the front panel of the device using intuitively arranged screens with adjustable parameters for a given fraction collection series.</p><p><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Watrex_Nastaveni_treshold_limitu_pro_sber_frakci_pomoci_sberace_frakci_FC_1_f48d645dfc/Watrex-Nastaveni-treshold-limitu-pro-sber-frakci-pomoci-sberace-frakci-FC1.jpg" alt="Watrex: Setting the treshold limit for fraction collection using the FC1 fraction collector"></p><h3><strong>FEATURES</strong></h3><ul><li>Simple operation</li><li>Color touch panel control</li><li>Optional analog input</li><li>Selection of rack types</li><li>Clarity CDS supported</li></ul><h3><strong>TECHNICAL SPECIFICATION</strong></h3><ul><li><strong>Max. flow:</strong> 50 ml/min</li><li><strong>Wetted Materials:</strong> PTFE, PEEK</li><li><strong>User control:</strong> Color touch panel</li><li><strong>PC connection:</strong> USB</li><li><strong>External control:</strong> TTL (contact closure) - RUN, STOP, NEXT, COLLECT</li><li><strong>Power supply:</strong> 24V DC external power supply</li></ul><h3><strong>Ordering information:</strong></h3><h5><strong>PN/Component:</strong></h5><ul><li><strong>SFC101-001</strong> Streamline™ FC1 Fraction Collector</li><li><strong>SFC101-002</strong> Cooling option for FC1 Fraction Collector</li><li><strong>SFC101-003</strong> Analog Signal Monitoring, Input for FC1 Fraction Collector</li></ul><p><strong>You can also visit this product on the </strong><a target="_blank" rel="noopener noreferrer" href="https://watrex.com/obchod/chromatography/dedicated-instruments/streamline-fc1-fraction-collector/?utm_source=labrulez&amp;utm_medium=propagace&amp;utm_campaign=labrulez_produkty"><strong>Watrex website</strong></a><strong>.</strong></p>

Products from category Sample preparation automation focused on HPLC - 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