The clinical urgency is difficult to overstate. H. pylori infects a large proportion of the global population and is firmly linked to chronic active gastritis, peptic ulcer disease, gastric mucosal atrophy, intestinal metaplasia, and gastric adenocarcinoma. Prospective cohort evidence has connected infection to subsequent gastric cancer development, and meta-analytic data indicate that eradication therapy can reduce cancer risk in appropriate populations. The Kyoto global consensus went so far as to define H. pylori gastritis as an infectious disease that should be diagnosed and treated wherever detected. Yet the therapeutic arsenal is weakening. The Maastricht VI/Florence Consensus Report urges clinicians to tailor regimens to local resistance patterns and prior antibiotic exposure, while the 2024 American College of Gastroenterology guideline now advises against empirical clarithromycin triple therapy unless susceptibility has been confirmed, recommending 14-day optimized bismuth quadruple therapy as the default empirical option when susceptibility is unknown.

Into this resistant landscape, the study’s authors introduce a deliberately small and transparent computational experiment. They selected three targets representing complementary biological functions: H. pylori urease, the nickel-dependent virulence enzyme that allows the bacterium to survive gastric acid by hydrolyzing urea; DNA gyrase subunit A, essential for DNA topology and replication; and shikimate kinase, part of a biosynthetic pathway present in many microorganisms and plants but absent from humans. Crystallographic structures from the Protein Data Bank served for urease (PDB 1E9Y, with its nickel-containing architecture carefully preserved) and shikimate kinase (PDB 1ZUH), while DNA gyrase A was represented by an AlphaFold model because a suitable experimental structure for blind docking was unavailable. Ligands were docked blindly using CB-Dock2, an automated server combining cavity detection with Vina-type scoring, and the resulting poses were inspected in three dimensions and mapped residue-by-residue in two-dimensional diagrams.

The choice of ligands was grounded in prior experimental data rather than computational convenience. Niclosamide, a salicylanilide anthelmintic long used against tapeworms, had already demonstrated striking anti-H. pylori activity in vitro: it inhibited strain 60190 with a minimum inhibitory concentration of 0.25 micrograms per milliliter, remained active at acidic pH, showed partial synergy with metronidazole and proton pump inhibitors, reduced bacterial adhesion and invasion of gastric epithelial cells by roughly 3 log CFU, and produced no detectable resistance after prolonged exposure in a Galleria mellonella infection model. Berberine, a quaternary ammonium alkaloid from plants such as Berberis species, carries clinical credentials of its own. A randomized phase IV trial found that a 14-day quadruple regimen containing berberine achieved eradication rates of 90.1 percent by intention-to-treat and 91.3 percent per protocol, non-inferior to a bismuth-containing regimen, and a later meta-analysis reported that adding berberine to standard triple therapy improved eradication with a risk ratio of 1.22.

The docking results positioned both candidates favorably. Against urease, niclosamide and berberine tied for the most negative score at –8.5 kcal/mol, outperforming levofloxacin’s –7.9 kcal/mol. Berberine again led against DNA gyrase A at –8.5 kcal/mol, ahead of niclosamide at –7.8 and levofloxacin at –7.5 kcal/mol. Shikimate kinase proved the least favorable target overall, with berberine at –7.3, levofloxacin at –7.0, and niclosamide at –6.9 kcal/mol. Across all three targets, berberine posted the most negative descriptive mean score at –8.10 ± 0.69 kcal/mol, compared with –7.73 ± 0.80 for niclosamide and –7.47 ± 0.45 for levofloxacin. The authors are categorical that these Vina-type outputs are ranking scores only, not binding free energies or affinity constants; a favorable docked score can occur even for a compound that fails to bind in solution.

Perhaps the most technically instructive finding emerged from the two-dimensional interaction maps: identical scores can mask entirely different binding modes. At urease, where niclosamide and berberine shared the same –8.5 kcal/mol value, their predicted stabilization patterns diverged sharply. Berberine’s pose relied mainly on pi-alkyl, pi-sigma, and hydrophobic contacts with residues including LEU A:13, ALA A:16, VAL A:33, PHE B:441, and TYR A:32, while niclosamide’s pose combined conventional hydrogen bonds with hydrophobic, pi-related, and van der Waals contacts involving VAL B:473, TYR B:475, PRO B:472, and MET A:12. At DNA gyrase A, berberine’s aromatic contacts with PHE A:549 and TYR A:525 drove its top ranking, whereas levofloxacin interacted with ASP A:91, ARG A:95, and GLN A:98, including one unfavorable positive-positive contact. The authors caution, however, that the isolated DNA gyrase A model cannot reproduce the DNA–enzyme–drug ternary complex on which fluoroquinolone pharmacodynamics actually depends.

The ADMET profiling added a sobering pharmacokinetic dimension. All three compounds showed zero Lipinski rule-of-five violations and identical bioavailability scores of 0.55, with high predicted gastrointestinal absorption, but their developability profiles differ meaningfully. Niclosamide’s consensus logP of 3.78 and topological polar surface area of 49.33 square angstroms predict membrane permeability, yet its poor aqueous solubility makes formulation-oriented work essential. Berberine’s permanent quaternary cationic structure, which was preserved in the docking preparation, is associated with complex, formulation-dependent exposure that demands experimental confirmation. Neither descriptor set, the study emphasizes, constitutes evidence of therapeutic suitability; they flag questions about exposure, solubility, and formulation that only laboratory measurement can resolve.

The methodological self-awareness sets this study apart from much of the computational drug-repurposing literature. The authors explicitly note that no redocking validation, receiver operating characteristic benchmarking, molecular dynamics simulations, or MM/GBSA or MM/PBSA free-energy analyses were performed, meaning pose accuracy and screening enrichment cannot be claimed. Alternative protonation and tautomeric states of the ligands were not systematically enumerated, a constraint that can influence both poses and scores. Thermodynamically, they explain, a docking score approximates none of the free-state, solvation, desolvation, and entropic contributions required for a true binding free energy, and virtual screening workflows carry substantial false-positive rates. With only three ligands and three targets, no inferential statistics were applied; all summaries are purely descriptive of this specific matrix.

The study also situates itself honestly within prior evidence. The docking results neither reproduce niclosamide’s previously observed antibacterial effects nor identify their mechanism; instead they generate a separate, target-oriented hypothesis that urease, gyrase, and shikimate kinase engagement could be tested experimentally. Similarly, the mixed clinical record of berberine—a more recent randomized trial found no clear superiority for berberine-containing triple therapy, and reported MIC values against H. pylori vary widely by strain and method—means the alkaloid should be viewed as a scaffold for mechanistic and formulation-focused testing rather than a docking-supported monotherapy. The shikimate kinase results, with their small score differences, are downgraded to a lower-priority experimental hypothesis despite the target’s theoretical selectivity advantage.

What remains is a deliberately restricted but actionable set of next steps. The authors propose urease inhibition assays as the first priority, followed by broth microdilution or agar-dilution MIC determination against reference and clinical H. pylori strains, checkerboard combination testing with standard antibiotics, cytotoxicity screening on gastric epithelial cell models, and, if justified by results, molecular dynamics and post-docking free-energy analyses. Within this framework, berberine earns the most consistent score pattern, niclosamide remains the clearest repurposing candidate for urease-focused testing given its prior experimental pedigree, and levofloxacin serves its role as a clinically interpretable yardstick. None of these outputs demonstrates binding, enzyme inhibition, bacterial killing, or therapeutic efficacy—but as an exercise in reducing the experimental search space before costly microbiological testing, the study offers a model of how computational prioritization can be conducted with the caveats firmly attached.

Subject of Research: Computational docking and ADMET profiling of niclosamide and berberine against Helicobacter pylori urease, DNA gyrase A, and shikimate kinase

Article Title: Comparative molecular docking and ADMET profiling of niclosamide and berberine against multiple Helicobacter pylori enzymatic targets

Article References: Comparative molecular docking and ADMET profiling of niclosamide and berberine against multiple Helicobacter pylori enzymatic targets. (n.d.). https://doi.org/10.3897/pharmacia.73.e212118

Image Credits: AI Generated

DOI: 10.3897/pharmacia.73.e212118

Keywords: Helicobacter pylori, molecular docking, niclosamide, berberine, levofloxacin, ADMET, drug repurposing, urease, DNA gyrase, shikimate kinase, antimicrobial resistance, in silico screening

The research team began with a deceptively simple question that has long frustrated scientists working at the intersection of environmental toxicology and the microbiome. It is well established that the trillions of microbes inhabiting the gut influence brain function and behavior, a relationship often described as the gut-brain axis. It is equally well established that environmental pollutants, which pervade modern life, can disrupt behavior and pose serious threats to ecological integrity and public health. What remained unclear was whether pollutant-induced shifts in the structure and function of the gut microbiome actually contribute to behavioral disturbances, or whether the microbiome’s role was merely a passive reflection of host illness. Even more tantalizing was the possibility, largely unexplored, that certain core symbiotic taxa might actively defend the host against the behavioral consequences of pollutant exposure.

To untangle this relationship, the investigators turned to the zebrafish, a small tropical fish that has become a workhorse of behavioral neuroscience. Zebrafish possess a conserved serotonergic system, display quantifiable anxiety-like behaviors, and are transparent enough and prolific enough to permit rigorous controlled experiments. The team established a model of anxiety-like behavior by exposing zebrafish to niclosamide, an anthelmintic and molluscicide whose growing presence in waterways makes it a representative pollutant of concern. Exposed fish exhibited the hallmarks of anxiety-like behavior, providing a reproducible platform for asking how the gut microbial community changes when the brain changes, and vice versa.

Microbial diversity analyses of the gut contents revealed pronounced differences in community structure between zebrafish displaying anxiety-like behavior and normal controls. The pollutant did not simply perturb the microbiome at random; rather, the compositional shifts were patterned and specific. Among the taxa whose relative abundance changed, one stood out. Through fecal microbiota transplantation experiments, in which gut contents from anxious fish were transferred to recipient animals, the researchers identified Cetobacterium as a key biomarker species associated with the anxious state. This genus of anaerobic, Gram-negative bacteria is a dominant member of the fish gut microbiome, and its depletion or alteration under pollutant pressure suggested that its loss might be part of the mechanism by which niclosamide drives behavioral change.

Correlation, however, is not causation, and this is where the study’s design becomes particularly compelling. To test whether Cetobacterium was merely a bystander or an active player, the researchers turned to germ-free zebrafish, animals raised entirely without microbes, which offer the cleanest possible experimental canvas for microbiome science. When the team orally reintroduced Cetobacterium to these microbe-free fish, the effect was striking: the bacterium effectively mitigated anxiety-like behavior. In other words, adding back a single symbiotic species was sufficient to rescue a behavioral phenotype, a result that elevates Cetobacterium from biomarker to functional agent and establishes a causal link between this microbe and the regulation of host emotional state.

With causality established, the researchers deployed integrated metabolomic and transcriptomic analyses to trace the molecular mechanism. Metabolomics profiles the small molecules in a biological system, while transcriptomics measures which genes are being actively expressed, and combining the two allows researchers to connect biochemical changes to the genetic programs that produce them. The analyses converged on a single pathway: tryptophan metabolism. Tryptophan is an essential amino acid obtained through the diet and serves as the obligate precursor for serotonin, known chemically as 5-hydroxytryptamine or 5-HT. The study demonstrated that Cetobacterium modulates host tryptophan metabolism in a way that increases serotonin levels in both the gut and the serum, the cell-rich fluid portion of blood that circulates throughout the body. This finding is significant because serotonin signaling is a central regulator of mood, anxiety, and behavior across vertebrates, and the gut is a major site of serotonin synthesis in many animals.

The mechanistic chain was then tested from the opposite direction, a hallmark of rigorous experimental logic. If Cetobacterium calms anxious fish by boosting serotonin production from tryptophan, then blocking serotonin synthesis should abolish the protective effect. The researchers used pharmacological inhibition of tryptophan hydroxylase, or TPH, the rate-limiting enzyme that catalyzes the first and critical step in converting tryptophan into serotonin. When TPH was inhibited, serotonin levels fell, and, crucially, the anxiolytic effects of Cetobacterium were markedly attenuated. The bacterium’s benefit depended on the host’s ability to manufacture serotonin, confirming that the microbe acts upstream of a defined neurochemical pathway rather than through some diffuse or nonspecific mechanism. This loss-of-function experiment transforms the study from an observational association into a mechanistic account: pollutant disrupts the microbiome, loss of Cetobacterium impairs tryptophan-to-serotonin conversion, serotonin drops, and anxiety-like behavior emerges; restore the bacterium, and the pathway is reactivated.

The implications of this work extend well beyond the aquarium. Niclosamide and similar pollutants are genuine environmental contaminants, and aquatic ecosystems worldwide are under chronic chemical pressure from agricultural runoff, industrial discharge, and pharmaceutical residues. If core gut symbionts in fish serve as a first line of defense against pollutant-induced behavioral disruption, then the health of the microbiome becomes an important variable in assessing ecological risk. Pollutants may harm wildlife not only through direct neurotoxicity but also indirectly, by eroding the beneficial microbial partners that normally support normal brain function. Conversely, microbial interventions, whether through probiotics, habitat management, or aquaculture feed formulations that support symbiont abundance, could offer a novel strategy for protecting animal welfare and cognitive function in contaminated environments.

For human health, the study offers a provocative proof of principle, though the authors’ findings were obtained in zebrafish and direct extrapolation to humans requires caution. Cetobacterium is a fish-associated genus, and the human gut harbors its own constellation of core symbionts, some of which are known to influence tryptophan availability and serotonergic signaling. The conceptual framework, however, travels well: a defined gut microbe, a defined metabolic pathway, a defined neurotransmitter, and a defined behavioral outcome, all connected in a causal chain verified by transplantation, reconstitution, and pharmacological blockade. This level of mechanistic resolution is rare in microbiome science, where studies often stop at correlational community profiling, and it sets a template for how future work in mammals, including humans, might identify protective taxa and validate their mechanisms with equal rigor.

The research, supported by the National Natural Science Foundation of China, the Shenzhen Science and Technology Program, and the China Postdoctoral Science Foundation, was conducted under the ethical guidelines for the care and use of laboratory animals with approval from the Animal Ethics and Welfare Committee of Northwest A&F University. As environmental pollution intensifies and mental health disorders rise globally, the convergence of these two crises in a single microbial pathway is a finding that demands attention. The gut, it turns out, may be one of the places where the body mounts its quietest and most effective resistance to the chemical insults of the modern world, and Cetobacterium somerae has just given scientists a detailed map of how that resistance works.

Subject of Research: The role of the gut symbiont Cetobacterium somerae in mitigating pollutant-induced anxiety-like behavior through modulation of host tryptophan metabolism and serotonin signaling in zebrafish.

Article Title: Cetobacterium somerae mitigates pollutant-induced behavioral abnormalities by modulating host tryptophan metabolism

Article References: Qi, X., Zhang, Y., Yang, K., Wang, G., & Ling, F. (2026). Cetobacterium somerae mitigates pollutant-induced behavioral abnormalities by modulating host tryptophan metabolism. Microbiome. https://doi.org/10.1186/s40168-026-02526-2

Image Credits: AI Generated

DOI: 10.1186/s40168-026-02526-2

Keywords: Cetobacterium somerae, gut-brain axis, microbiome, anxiety-like behavior, zebrafish, niclosamide, tryptophan metabolism, serotonin, tryptophan hydroxylase, fecal microbiota transplantation, environmental pollutants, multi-omics

A team at Korea’s National Institute of Food and Drug Safety Evaluation, led by Ye-Bin Jang and corresponding author Mi-Ok Kim, has now closed that gap. Writing in Food Science of Animal Resources, the researchers describe an optimized liquid chromatography–tandem mass spectrometry (LC–MS/MS) method that simultaneously quantifies 18 structurally diverse anthelmintic and antiparasitic compounds across nine animal-derived food matrices: beef, pork, chicken, eggs, milk, porcine fat, flatfish, eel, and shrimp. Beyond niclosamide, the method brings rarely monitored compounds such as derquantel, bithionol, and nitroxinil into quantitative reach, expanding both the chemical and the biological scope of routine residue surveillance.

The analytical challenge is formidable because the target compounds span six major chemical classes with very different physicochemical personalities. Benzimidazoles such as triclabendazole attack larval and adult parasites alike; salicylanilides including closantel, rafoxanide, and niclosamide also knock down ectoparasites like ticks; tetrahydropyrimidines such as morantel and pyrantel act as nicotinic receptor agonists; imidazothiazoles like levamisole target roundworms; and the macrocyclic lactones—abamectin, ivermectin, doramectin, eprinomectin, and moxidectin—are large, extremely lipophilic molecules that cling stubbornly to fatty tissue. Add praziquantel and nitroxinil to the list, and a single run must coax compounds ranging from small polar bases to sprawling lipid-like structures through the same column and ion source.

Sample preparation began with the QuEChERS approach—Quick, Easy, Cheap, Effective, Rugged, and Safe—which uses salt-induced phase separation to pull analytes from homogenized tissue into acetonitrile. The team compared three salt formulations: the unbuffered Original method with magnesium sulfate and sodium chloride, the citrate-buffered EN 15662 version, and the acetate-buffered AOAC variant. The verdict was decisive. In flatfish, the buffered methods produced calibration curves for abamectin with coefficients of determination of just 0.2304 and 0.0385—essentially useless—while the Original salts delivered R² values above 0.99 for all 18 compounds. The researchers attribute the failure of buffered systems to citrate and acetate ions altering salting-out efficiency and promoting co-extraction of lipids, proteins, and phospholipids, which then suppress ionization of the lipophilic macrocyclic lactones during electrospray.

Extraction used acetonitrile acidified with 0.1% formic acid, a combination known to improve recovery and precision for veterinary drugs in animal tissue. Clean-up followed with dispersive solid-phase extraction, and here the sorbent recipe mattered enormously. C18 alone left chlorfluazuron, levamisole, triclabendazole, and keto-triclabendazole with substandard linearity; PSA alone failed for chlorfluazuron and triclabendazole. Only the pairing of 400 milligrams of PSA with 400 milligrams of C18, plus 1,200 milligrams of magnesium sulfate, achieved R² values of at least 0.99 across the entire panel. PSA’s amino groups mop up organic acids and sugars, while C18 adsorbs nonpolar fats and fat-soluble interferences—a synergy the team standardized by purifying a fixed 8-milliliter extract volume for every matrix.

On the instrument side, chromatographic separation ran on a Waters Xbridge C18 column with a gradient of water containing 5 millimolar ammonium formate and 0.1% formic acid against acetonitrile with 0.1% formic acid. Retention times spanned from 1.9 minutes for morantel to 6.4 minutes for ivermectin. Detection used a Shimadzu LCMS-8060 triple quadrupole in multiple reaction monitoring mode, switching between positive and negative electrospray ionization, with precursor ions, product ions, and collision energies optimized by direct infusion of standards. The most intense transition served for quantification while secondary transitions confirmed identity.

Matrix effects proved to be the method’s central analytical adversary. Co-extracted lipids and proteins distort electrospray ionization, and the team measured signal changes of at least 20% for most analytes. Ion suppression dominated, ranging down to −96.08%, with abamectin, levamisole, pyrantel, and triclabendazole suppressed in every single matrix. Moxidectin, by contrast, showed ion enhancement in several foods, including chicken, milk, and all three fishery products. Rather than turning to isotope-labeled internal standards—impractical and costly for an 18-compound panel—the researchers built matrix-matched calibration curves in blank extracts of each food, so standards and samples ionize under identical chemical conditions and systematic signal bias cancels out at the quantification stage.

Validated under CODEX guideline CAC/GL-71, the method met every performance criterion. Matrix-matched calibration curves exceeded R² of 0.99 for all compounds in all nine matrices. Limits of quantification ranged from 0.0033 to 0.0054 milligrams per kilogram, all below half of the established MRLs. Intraday recovery and precision across the matrices fell between 72.0 and 119.1% with coefficients of variation no higher than 18.2%, comfortably inside CODEX windows, and interday testing on three consecutive days with two analysts held recoveries between 72.0 and 118.7% with CVs at or below 19.0%.

To test real-world utility, the team analyzed 60 market samples—30 livestock and 30 fishery products chosen for high Korean consumption. None of the 18 target analytes was detected, a reassuring snapshot of the domestic supply, though the authors stress that continued surveillance remains essential. The method’s true significance lies in what it enables going forward: quantitative enforcement for drugs like niclosamide that previously escaped numeric scrutiny, a single validated workflow spanning meat, dairy, eggs, and seafood, and a technical foundation for setting and revising safety standards. As veterinary drug use intensifies globally and resistant parasites push dosing upward, tools like this one turn regulatory limits from paper promises into measurable, enforceable protections for the food supply.

Subject of Research: Development and validation of a QuEChERS-based LC–MS/MS method for quantifying multiclass veterinary anthelmintic residues in animal-derived foods

Article Title: Optimized LC–MS/MS method for simultaneous determination of multiclass veterinary anthelmintic residues in animal-derived matrices

Article References: Optimized LC–MS/MS method for simultaneous determination of multiclass veterinary anthelmintic residues in animal-derived matrices. (n.d.). https://doi.org/10.1007/s44463-026-00098-1

Image Credits: AI Generated

DOI: 10.1007/s44463-026-00098-1

Keywords: anthelmintics, LC-MS/MS, veterinary drug residues, QuEChERS, food safety, maximum residue limits, matrix-matched calibration, livestock products, fishery products, niclosamide, mass spectrometry, residue monitoring